<?xml version="1.0" encoding="us-ascii" standalone="yes"?>
<!--XBRL Document Created with XBRLMaster-->
<!--Version: 2.3.08-->
<!--Based on XBRL 2.1-->
<!--Date of creation: 04/01/2026-->
<!--Software architectural design and coding: A'c Dharmapremananda Avt.-->
<!--Copyright (c) 2026 I-NET Business Solutions, Inc. All Rights Reserved.-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://class.com/role/Cover" xlink:href="class-20251231.xsd#Cover" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConsolidatedBalanceSheets" xlink:href="class-20251231.xsd#ConsolidatedBalanceSheets" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:href="class-20251231.xsd#ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConsolidatedStatementsOfOperations" xlink:href="class-20251231.xsd#ConsolidatedStatementsOfOperations" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConsolidatedStatementsOfChangesInShareholdersEquityDeficit" xlink:href="class-20251231.xsd#ConsolidatedStatementsOfChangesInShareholdersEquityDeficit" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConsolidatedStatementsOfCashFlows" xlink:href="class-20251231.xsd#ConsolidatedStatementsOfCashFlows" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/InsiderTradingArrangements" xlink:href="class-20251231.xsd#InsiderTradingArrangements" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/DescriptionOfTheBusinessAndBasisOfPresentation" xlink:href="class-20251231.xsd#DescriptionOfTheBusinessAndBasisOfPresentation" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="class-20251231.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/PropertyAndEquipmentNet" xlink:href="class-20251231.xsd#PropertyAndEquipmentNet" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/InvestmentAccounts" xlink:href="class-20251231.xsd#InvestmentAccounts" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IntangibleAssets" xlink:href="class-20251231.xsd#IntangibleAssets" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/Leases" xlink:href="class-20251231.xsd#Leases" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/AccruedLiabilitiesAndOtherPayables" xlink:href="class-20251231.xsd#AccruedLiabilitiesAndOtherPayables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IncomeTaxes" xlink:href="class-20251231.xsd#IncomeTaxes" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RelatedParties" xlink:href="class-20251231.xsd#RelatedParties" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConvertibleNotes" xlink:href="class-20251231.xsd#ConvertibleNotes" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/WarrantLiabilities" xlink:href="class-20251231.xsd#WarrantLiabilities" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RecurringFairValueMeasurements" xlink:href="class-20251231.xsd#RecurringFairValueMeasurements" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SegmentInformationAndRevenueAnalysis" xlink:href="class-20251231.xsd#SegmentInformationAndRevenueAnalysis" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/CommitmentsAndContingencies" xlink:href="class-20251231.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/Equity" xlink:href="class-20251231.xsd#Equity" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConcentrationOfRisk" xlink:href="class-20251231.xsd#ConcentrationOfRisk" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SubsequentEvent" xlink:href="class-20251231.xsd#SubsequentEvent" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="class-20251231.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:href="class-20251231.xsd#SummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/PropertyAndEquipmentNetTables" xlink:href="class-20251231.xsd#PropertyAndEquipmentNetTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/InvestmentAccountsTables" xlink:href="class-20251231.xsd#InvestmentAccountsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IntangibleAssetsTables" xlink:href="class-20251231.xsd#IntangibleAssetsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/LeasesTables" xlink:href="class-20251231.xsd#LeasesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/AccruedLiabilitiesAndOtherPayablesTables" xlink:href="class-20251231.xsd#AccruedLiabilitiesAndOtherPayablesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IncomeTaxesTables" xlink:href="class-20251231.xsd#IncomeTaxesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RelatedPartiesTables" xlink:href="class-20251231.xsd#RelatedPartiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConvertibleNotesTables" xlink:href="class-20251231.xsd#ConvertibleNotesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/WarrantLiabilitiesTables" xlink:href="class-20251231.xsd#WarrantLiabilitiesTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RecurringFairValueMeasurementsTables" xlink:href="class-20251231.xsd#RecurringFairValueMeasurementsTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SegmentInformationAndRevenueAnalysisTables" xlink:href="class-20251231.xsd#SegmentInformationAndRevenueAnalysisTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/EquityTables" xlink:href="class-20251231.xsd#EquityTables" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/DescriptionOfTheBusinessAndBasisOfPresentationDetailsNarrative" xlink:href="class-20251231.xsd#DescriptionOfTheBusinessAndBasisOfPresentationDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:href="class-20251231.xsd#SummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:href="class-20251231.xsd#SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/PropertyAndEquipmentNetDetails" xlink:href="class-20251231.xsd#PropertyAndEquipmentNetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/PropertyAndEquipmentNetDetailsNarrative" xlink:href="class-20251231.xsd#PropertyAndEquipmentNetDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/InvestmentAccountsDetails" xlink:href="class-20251231.xsd#InvestmentAccountsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/InvestmentAccountsDetailsNarrative" xlink:href="class-20251231.xsd#InvestmentAccountsDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IntangibleAssetsDetails" xlink:href="class-20251231.xsd#IntangibleAssetsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IntangibleAssetsDetailsNarrative" xlink:href="class-20251231.xsd#IntangibleAssetsDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/LeasesDetails" xlink:href="class-20251231.xsd#LeasesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/LeasesDetails1" xlink:href="class-20251231.xsd#LeasesDetails1" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/LeasesDetailsNarrative" xlink:href="class-20251231.xsd#LeasesDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/AccruedLiabilitiesAndOtherPayablesDetails" xlink:href="class-20251231.xsd#AccruedLiabilitiesAndOtherPayablesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IncomeTaxesDetails" xlink:href="class-20251231.xsd#IncomeTaxesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IncomeTaxesDetails1" xlink:href="class-20251231.xsd#IncomeTaxesDetails1" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IncomeTaxesDetails2" xlink:href="class-20251231.xsd#IncomeTaxesDetails2" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/IncomeTaxesDetailsNarrative" xlink:href="class-20251231.xsd#IncomeTaxesDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RelatedPartiesDetails" xlink:href="class-20251231.xsd#RelatedPartiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RelatedPartiesDetails1" xlink:href="class-20251231.xsd#RelatedPartiesDetails1" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RelatedPartiesDetails2" xlink:href="class-20251231.xsd#RelatedPartiesDetails2" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RelatedPartiesDetails3" xlink:href="class-20251231.xsd#RelatedPartiesDetails3" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConvertibleNotesPayableDetails" xlink:href="class-20251231.xsd#ConvertibleNotesPayableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConvertibleNotesPayableDetails1" xlink:href="class-20251231.xsd#ConvertibleNotesPayableDetails1" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConvertibleNotesPayableDetails2" xlink:href="class-20251231.xsd#ConvertibleNotesPayableDetails2" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConvertibleNotesPayableDetails3" xlink:href="class-20251231.xsd#ConvertibleNotesPayableDetails3" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConvertibleNotesPayableDetailsNarrative" xlink:href="class-20251231.xsd#ConvertibleNotesPayableDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/WarrantLiabilitiesDetails" xlink:href="class-20251231.xsd#WarrantLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/WarrantLiabilitiesDetailsNarrative" xlink:href="class-20251231.xsd#WarrantLiabilitiesDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/RecurringFairValueMeasurementsDetails" xlink:href="class-20251231.xsd#RecurringFairValueMeasurementsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SegmentInformationAndRevenueAnalysisDetails" xlink:href="class-20251231.xsd#SegmentInformationAndRevenueAnalysisDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/EquityDetails" xlink:href="class-20251231.xsd#EquityDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/EquityDetailsNarrative" xlink:href="class-20251231.xsd#EquityDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/ConcentrationOfRiskDetailsNarrative" xlink:href="class-20251231.xsd#ConcentrationOfRiskDetailsNarrative" xlink:type="simple" />
  <link:roleRef roleURI="http://class.com/role/SubsequentEventDetailsNarrative" xlink:href="class-20251231.xsd#SubsequentEventDetailsNarrative" xlink:type="simple" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/Cover" xlink:title="00000001 - Document - Document and Entity Information" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConsolidatedBalanceSheets" xlink:title="110200 - Statement - CONSOLIDATED BALANCE SHEETS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaapAssetsCurrent" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" />
    <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaapPrepaidExpenseAndOtherAssetsCurrent" />
    <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapPrepaidExpenseAndOtherAssetsCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_DueFromRelatedPartyCurrent" xlink:label="loc_classDueFromRelatedPartyCurrent" />
    <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_classDueFromRelatedPartyCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsNoncurrent" xlink:label="loc_us-gaapAssetsNoncurrent" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet" />
    <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNoncurrent" xlink:to="loc_us-gaapPropertyPlantAndEquipmentNet" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaapOperatingLeaseRightOfUseAsset" />
    <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNoncurrent" xlink:to="loc_us-gaapOperatingLeaseRightOfUseAsset" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Investments" xlink:label="loc_us-gaapInvestments" />
    <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNoncurrent" xlink:to="loc_us-gaapInvestments" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepositsAssetsNoncurrent" xlink:label="loc_us-gaapDepositsAssetsNoncurrent" />
    <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNoncurrent" xlink:to="loc_us-gaapDepositsAssetsNoncurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaapIntangibleAssetsNetExcludingGoodwill" />
    <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNoncurrent" xlink:to="loc_us-gaapIntangibleAssetsNetExcludingGoodwill" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedInvestmentsNoncurrent" xlink:label="loc_us-gaapRestrictedInvestmentsNoncurrent" />
    <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsNoncurrent" xlink:to="loc_us-gaapRestrictedInvestmentsNoncurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets" xlink:label="loc_us-gaapAssets" />
    <link:calculationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapAssetsCurrent" xlink:type="arc" weight="1" />
    <link:calculationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapAssetsNoncurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaapLiabilitiesCurrent" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaapAccountsPayableCurrent" />
    <link:calculationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapAccountsPayableCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestPayableCurrent" xlink:label="loc_us-gaapInterestPayableCurrent" />
    <link:calculationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapInterestPayableCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaapDeferredRevenueCurrent" />
    <link:calculationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapDeferredRevenueCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_DueToRelatedPartyCurrent" xlink:label="loc_classDueToRelatedPartyCurrent" />
    <link:calculationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_classDueToRelatedPartyCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaapOperatingLeaseLiabilityCurrent" />
    <link:calculationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapOperatingLeaseLiabilityCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaapAccountsPayableAndOtherAccruedLiabilitiesCurrent" />
    <link:calculationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapAccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaapLiabilitiesNoncurrent" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConvertibleLongTermNotesPayable" xlink:label="loc_us-gaapConvertibleLongTermNotesPayable" />
    <link:calculationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesNoncurrent" xlink:to="loc_us-gaapConvertibleLongTermNotesPayable" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="loc_us-gaapOperatingLeaseLiabilityNoncurrent" />
    <link:calculationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesNoncurrent" xlink:to="loc_us-gaapOperatingLeaseLiabilityNoncurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_WarrantLiabilitiesNoncurrent" xlink:label="loc_classWarrantLiabilitiesNoncurrent" />
    <link:calculationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesNoncurrent" xlink:to="loc_classWarrantLiabilitiesNoncurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="loc_us-gaapDeferredIncomeTaxLiabilitiesNet" />
    <link:calculationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesNoncurrent" xlink:to="loc_us-gaapDeferredIncomeTaxLiabilitiesNet" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaapLiabilities" />
    <link:calculationArc order="23" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapLiabilitiesCurrent" xlink:type="arc" weight="1" />
    <link:calculationArc order="24" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapLiabilitiesNoncurrent" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaapAdditionalPaidInCapital" />
    <link:calculationArc order="25" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapAdditionalPaidInCapital" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit" />
    <link:calculationArc order="26" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaapPreferredStockValue" />
    <link:calculationArc order="27" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapPreferredStockValue" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaapCommonStockValue" />
    <link:calculationArc order="28" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapCommonStockValue" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaapLiabilitiesAndStockholdersEquity" />
    <link:calculationArc order="29" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapLiabilities" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaapCommitmentsAndContingencies" />
    <link:calculationArc order="30" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapCommitmentsAndContingencies" xlink:type="arc" weight="1" />
    <link:calculationArc order="31" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapStockholdersEquity" xlink:type="arc" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:title="110201 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConsolidatedStatementsOfOperations" xlink:title="124100 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues" xlink:label="loc_us-gaapRevenues" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_RevenueFromServices" xlink:label="loc_classRevenueFromServices" />
    <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapRevenues" xlink:to="loc_classRevenueFromServices" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_RevenueFromConsultingServicesRelatedParty" xlink:label="loc_classRevenueFromConsultingServicesRelatedParty" />
    <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapRevenues" xlink:to="loc_classRevenueFromConsultingServicesRelatedParty" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaapCostOfRevenue" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="loc_us-gaapCostOfGoodsAndServicesSold" />
    <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCostOfRevenue" xlink:to="loc_us-gaapCostOfGoodsAndServicesSold" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaapGrossProfit" />
    <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapGrossProfit" xlink:to="loc_us-gaapRevenues" xlink:type="arc" weight="1" />
    <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapGrossProfit" xlink:to="loc_us-gaapCostOfRevenue" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaapOperatingExpenses" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaapSellingAndMarketingExpense" />
    <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapSellingAndMarketingExpense" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaapGeneralAndAdministrativeExpense" />
    <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapGeneralAndAdministrativeExpense" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaapResearchAndDevelopmentExpense" />
    <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapResearchAndDevelopmentExpense" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaapOperatingIncomeLoss" />
    <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingIncomeLoss" xlink:to="loc_us-gaapGrossProfit" xlink:type="arc" weight="1" />
    <link:calculationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingIncomeLoss" xlink:to="loc_us-gaapOperatingExpenses" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaapOtherNonoperatingIncomeExpense" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinancingInterestExpense" xlink:label="loc_us-gaapFinancingInterestExpense" />
    <link:calculationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_us-gaapFinancingInterestExpense" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_StakingRewardsIncome" xlink:label="loc_classStakingRewardsIncome" />
    <link:calculationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_classStakingRewardsIncome" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_GainLossOnChangeInFairValueOfConvertibleDebt" xlink:label="loc_classGainLossOnChangeInFairValueOfConvertibleDebt" />
    <link:calculationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_classGainLossOnChangeInFairValueOfConvertibleDebt" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaapGainsLossesOnExtinguishmentOfDebt" />
    <link:calculationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_us-gaapGainsLossesOnExtinguishmentOfDebt" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:label="loc_us-gaapDerivativeGainLossOnDerivativeNet" />
    <link:calculationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_us-gaapDerivativeGainLossOnDerivativeNet" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:label="loc_us-gaapImpairmentOfIntangibleAssetsFinitelived" />
    <link:calculationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_us-gaapImpairmentOfIntangibleAssetsFinitelived" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:label="loc_us-gaapInterestIncomeExpenseNonoperatingNet" />
    <link:calculationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_us-gaapInterestIncomeExpenseNonoperatingNet" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CryptoAssetRealizedGainLossNonoperating" xlink:label="loc_us-gaapCryptoAssetRealizedGainLossNonoperating" />
    <link:calculationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:to="loc_us-gaapCryptoAssetRealizedGainLossNonoperating" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <link:calculationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapOperatingIncomeLoss" xlink:type="arc" weight="1" />
    <link:calculationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
    <link:calculationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaapIncomeTaxExpenseBenefit" />
    <link:calculationArc order="23" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapIncomeTaxExpenseBenefit" xlink:type="arc" weight="-1" />
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConsolidatedStatementsOfChangesInShareholdersEquityDeficit" xlink:title="148600 - Statement - CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS EQUITY (DEFICIT)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConsolidatedStatementsOfCashFlows" xlink:title="170000 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss" xlink:label="loc_us-gaapProfitLoss" />
    <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapProfitLoss" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationAndAmortization" xlink:label="loc_us-gaapDepreciationAndAmortization" />
    <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapDepreciationAndAmortization" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" xlink:label="loc_us-gaapOperatingLeaseRightOfUseAssetAmortizationExpense" />
    <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapOperatingLeaseRightOfUseAssetAmortizationExpense" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeBenefitsAndShareBasedCompensation" xlink:label="loc_us-gaapEmployeeBenefitsAndShareBasedCompensation" />
    <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapEmployeeBenefitsAndShareBasedCompensation" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims" xlink:label="loc_us-gaapIssuanceOfStockAndWarrantsForServicesOrClaims" />
    <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIssuanceOfStockAndWarrantsForServicesOrClaims" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived" xlink:label="loc_us-gaapImpairmentOfIntangibleAssetsFinitelived" />
    <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapImpairmentOfIntangibleAssetsFinitelived" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:label="loc_us-gaapDeferredIncomeTaxesAndTaxCredits" />
    <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapDeferredIncomeTaxesAndTaxCredits" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeGainLossOnDerivativeNet" xlink:label="loc_us-gaapDerivativeGainLossOnDerivativeNet" />
    <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapDerivativeGainLossOnDerivativeNet" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CryptoAssetRealizedGainLossNonoperating" xlink:label="loc_us-gaapCryptoAssetRealizedGainLossNonoperating" />
    <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapCryptoAssetRealizedGainLossNonoperating" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_GainLossOnChangeInFairValueOfConvertibleDebt" xlink:label="loc_classGainLossOnChangeInFairValueOfConvertibleDebt" />
    <link:calculationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_classGainLossOnChangeInFairValueOfConvertibleDebt" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_IssuanceOfStocksForWaivingContractualRestrictionAmount" xlink:label="loc_classIssuanceOfStocksForWaivingContractualRestrictionAmount" />
    <link:calculationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_classIssuanceOfStocksForWaivingContractualRestrictionAmount" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_StakingRewardsIncome" xlink:label="loc_classStakingRewardsIncome" />
    <link:calculationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_classStakingRewardsIncome" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_IncreaseDecreaseInDueFromRelatedParty" xlink:label="loc_classIncreaseDecreaseInDueFromRelatedParty" />
    <link:calculationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_classIncreaseDecreaseInDueFromRelatedParty" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaapIncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
    <link:calculationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInDepositOtherAssets" xlink:label="loc_us-gaapIncreaseDecreaseInDepositOtherAssets" />
    <link:calculationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInDepositOtherAssets" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaapIncreaseDecreaseInAccountsPayable" />
    <link:calculationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccountsPayable" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:label="loc_us-gaapIncreaseDecreaseInInterestPayableNet" />
    <link:calculationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInInterestPayableNet" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaapIncreaseDecreaseInDeferredRevenue" />
    <link:calculationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInDeferredRevenue" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:label="loc_us-gaapIncreaseDecreaseInOperatingLeaseLiability" />
    <link:calculationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInOperatingLeaseLiability" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_IncreaseDecreaseInDueToRelatedParty" xlink:label="loc_classIncreaseDecreaseInDueToRelatedParty" />
    <link:calculationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_classIncreaseDecreaseInDueToRelatedParty" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaapIncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities" />
    <link:calculationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaapPaymentsToAcquirePropertyPlantAndEquipment" />
    <link:calculationArc order="23" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapPaymentsToAcquirePropertyPlantAndEquipment" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentForAcquisitionCryptoAsset" xlink:label="loc_us-gaapPaymentForAcquisitionCryptoAsset" />
    <link:calculationArc order="24" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapPaymentForAcquisitionCryptoAsset" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquireIntangibleAssets" xlink:label="loc_us-gaapPaymentsToAcquireIntangibleAssets" />
    <link:calculationArc order="25" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapPaymentsToAcquireIntangibleAssets" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromConvertibleDebt" xlink:label="loc_us-gaapProceedsFromConvertibleDebt" />
    <link:calculationArc order="26" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromConvertibleDebt" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:label="loc_us-gaapProceedsFromIssuanceOfPrivatePlacement" />
    <link:calculationArc order="27" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromIssuanceOfPrivatePlacement" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="class-20251231.xsd#class_ProceedsFromTheReverseRecapitalization" xlink:label="loc_classProceedsFromTheReverseRecapitalization" />
    <link:calculationArc order="28" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_classProceedsFromTheReverseRecapitalization" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfRelatedPartyDebt" xlink:label="loc_us-gaapRepaymentsOfRelatedPartyDebt" />
    <link:calculationArc order="29" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapRepaymentsOfRelatedPartyDebt" xlink:type="arc" weight="-1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromRelatedPartyDebt" xlink:label="loc_us-gaapProceedsFromRelatedPartyDebt" />
    <link:calculationArc order="30" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromRelatedPartyDebt" xlink:type="arc" weight="1" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" />
    <link:calculationArc order="31" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:type="arc" weight="1" />
    <link:calculationArc order="32" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:type="arc" weight="1" />
    <link:calculationArc order="33" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:type="arc" weight="1" />
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/InsiderTradingArrangements" xlink:title="170001 - Disclosure - Insider Trading Arrangements" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/DescriptionOfTheBusinessAndBasisOfPresentation" xlink:title="995551 - Disclosure - Description of the Business and Basis of Presentation" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SummaryOfSignificantAccountingPolicies" xlink:title="995552 - Disclosure - Summary of Significant Accounting Policies" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/PropertyAndEquipmentNet" xlink:title="995553 - Disclosure - Property and Equipment, net" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/InvestmentAccounts" xlink:title="995554 - Disclosure - Investment accounts" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IntangibleAssets" xlink:title="995555 - Disclosure - Intangible Assets" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/Leases" xlink:title="995556 - Disclosure - Leases" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/AccruedLiabilitiesAndOtherPayables" xlink:title="995557 - Disclosure - Accrued Liabilities and Other Payables" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IncomeTaxes" xlink:title="995558 - Disclosure - Income Taxes" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RelatedParties" xlink:title="995559 - Disclosure - Related parties" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConvertibleNotes" xlink:title="995560 - Disclosure - Convertible notes" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/WarrantLiabilities" xlink:title="995561 - Disclosure - Warrant Liabilities" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RecurringFairValueMeasurements" xlink:title="995562 - Disclosure - Recurring fair value measurements" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SegmentInformationAndRevenueAnalysis" xlink:title="995563 - Disclosure - Segment information and revenue analysis" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/CommitmentsAndContingencies" xlink:title="995564 - Disclosure - Commitments and Contingencies" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/Equity" xlink:title="995565 - Disclosure - Equity" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConcentrationOfRisk" xlink:title="995566 - Disclosure - Concentration of risk" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SubsequentEvent" xlink:title="995567 - Disclosure - Subsequent Event" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="995568 - Disclosure - Summary of Significant Accounting Policies (Policies)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:title="995569 - Disclosure - Summary of Significant Accounting Policies (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/PropertyAndEquipmentNetTables" xlink:title="995570 - Disclosure - Property and Equipment, net (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/InvestmentAccountsTables" xlink:title="995571 - Disclosure - Investment accounts (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IntangibleAssetsTables" xlink:title="995572 - Disclosure - Intangible Assets (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/LeasesTables" xlink:title="995573 - Disclosure - Leases (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/AccruedLiabilitiesAndOtherPayablesTables" xlink:title="995574 - Disclosure - Accrued Liabilities and Other Payables (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IncomeTaxesTables" xlink:title="995575 - Disclosure - Income Taxes (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RelatedPartiesTables" xlink:title="995576 - Disclosure - Related parties (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConvertibleNotesTables" xlink:title="995577 - Disclosure - Convertible notes (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/WarrantLiabilitiesTables" xlink:title="995578 - Disclosure - Warrant Liabilities (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RecurringFairValueMeasurementsTables" xlink:title="995579 - Disclosure - Recurring fair value measurements (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SegmentInformationAndRevenueAnalysisTables" xlink:title="995580 - Disclosure - Segment information and revenue analysis (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/EquityTables" xlink:title="995581 - Disclosure - Equity (Tables)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/DescriptionOfTheBusinessAndBasisOfPresentationDetailsNarrative" xlink:title="995582 - Disclosure - Description of the Business and Basis of Presentation (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SummaryOfSignificantAccountingPoliciesDetails" xlink:title="995583 - Disclosure - Summary of Significant Accounting Policies (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:title="995584 - Disclosure - Summary of Significant Accounting Policies (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/PropertyAndEquipmentNetDetails" xlink:title="995585 - Disclosure - Property and Equipment, net (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/PropertyAndEquipmentNetDetailsNarrative" xlink:title="995586 - Disclosure - Property and Equipment, net (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/InvestmentAccountsDetails" xlink:title="995587 - Disclosure - Investment accounts (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/InvestmentAccountsDetailsNarrative" xlink:title="995588 - Disclosure - Investment accounts (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IntangibleAssetsDetails" xlink:title="995589 - Disclosure - Intangible Assets (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IntangibleAssetsDetailsNarrative" xlink:title="995590 - Disclosure - Intangible Assets (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/LeasesDetails" xlink:title="995591 - Disclosure - Leases (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/LeasesDetails1" xlink:title="995592 - Disclosure - Leases (Details 1)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/LeasesDetailsNarrative" xlink:title="995593 - Disclosure - Leases (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/AccruedLiabilitiesAndOtherPayablesDetails" xlink:title="995594 - Disclosure - Accrued Liabilities and Other Payables (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IncomeTaxesDetails" xlink:title="995595 - Disclosure - Income Taxes (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IncomeTaxesDetails1" xlink:title="995596 - Disclosure - Income Taxes (Details 1)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IncomeTaxesDetails2" xlink:title="995597 - Disclosure - Income Taxes (Details 2)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/IncomeTaxesDetailsNarrative" xlink:title="995598 - Disclosure - Income Taxes (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RelatedPartiesDetails" xlink:title="995599 - Disclosure - Related parties (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RelatedPartiesDetails1" xlink:title="995600 - Disclosure - Related parties (Details 1)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RelatedPartiesDetails2" xlink:title="995601 - Disclosure - Related parties (Details 2)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RelatedPartiesDetails3" xlink:title="995602 - Disclosure - Related parties (Details 3)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConvertibleNotesPayableDetails" xlink:title="995603 - Disclosure - Convertible Notes Payable (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConvertibleNotesPayableDetails1" xlink:title="995604 - Disclosure - Convertible Notes Payable (Details 1)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConvertibleNotesPayableDetails2" xlink:title="995605 - Disclosure - Convertible Notes Payable (Details 2)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConvertibleNotesPayableDetails3" xlink:title="995606 - Disclosure - Convertible Notes Payable (Details 3)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConvertibleNotesPayableDetailsNarrative" xlink:title="995607 - Disclosure - Convertible Notes Payable (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/WarrantLiabilitiesDetails" xlink:title="995608 - Disclosure - Warrant Liabilities (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/WarrantLiabilitiesDetailsNarrative" xlink:title="995609 - Disclosure - Warrant Liabilities (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/RecurringFairValueMeasurementsDetails" xlink:title="995610 - Disclosure - Recurring fair value measurements (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SegmentInformationAndRevenueAnalysisDetails" xlink:title="995611 - Disclosure - Segment information and revenue analysis (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/EquityDetails" xlink:title="995612 - Disclosure - Equity (Details)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/EquityDetailsNarrative" xlink:title="995613 - Disclosure - Equity (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/ConcentrationOfRiskDetailsNarrative" xlink:title="995614 - Disclosure - Concentration of risk (Details Narrative)" />
  <link:calculationLink xlink:type="extended" xlink:role="http://class.com/role/SubsequentEventDetailsNarrative" xlink:title="995615 - Disclosure - Subsequent Event (Details Narrative)" />
</link:linkbase>
