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   <link:roleRef xlink:type="simple" xlink:href="81560001692D0424C949-2025-12-31.xsd#id_6" roleURI="https://www.somecgroup.com/xbrl/role/all/ias_1_role-610000"/>
   <link:roleRef xlink:type="simple" xlink:href="81560001692D0424C949-2025-12-31.xsd#id_11" roleURI="https://www.somecgroup.com/xbrl/role/all/ias_7_role-520000"/>
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   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Assets" xlink:label="ifrs-full_Assets" xlink:type="locator"/>
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      <link:calculationArc
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                          xlink:from="ifrs-full_Assets"
                          xlink:to="ifrs-full_NoncurrentAssets"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentAssets" xlink:label="ifrs-full_CurrentAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_Assets"
                          xlink:to="ifrs-full_CurrentAssets"
                            order="20.0"
                            weight="1.0"
                          xlink:type="arc"/>
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   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentAssets" xlink:label="ifrs-full_NoncurrentAssets" xlink:type="locator"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipment" xlink:label="ifrs-full_PropertyPlantAndEquipment" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_PropertyPlantAndEquipment"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxAssets" xlink:label="ifrs-full_DeferredTaxAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_DeferredTaxAssets"
                            order="100.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RightofuseAssets" xlink:label="ifrs-full_RightofuseAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_RightofuseAssets"
                            weight="1.0"
                            order="101.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InvestmentsInAssociatesAccountedForUsingEquityMethod" xlink:label="ifrs-full_InvestmentsInAssociatesAccountedForUsingEquityMethod" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_InvestmentsInAssociatesAccountedForUsingEquityMethod"
                            weight="1.0"
                            order="102.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentFinancialAssets" xlink:label="ifrs-full_NoncurrentFinancialAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_NoncurrentFinancialAssets"
                            weight="1.0"
                            order="103.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IntangibleAssetsAndGoodwill" xlink:label="ifrs-full_IntangibleAssetsAndGoodwill" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentAssets"
                          xlink:to="ifrs-full_IntangibleAssetsAndGoodwill"
                            weight="1.0"
                            order="104.0"
                          xlink:type="arc"/>
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   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentAssets" xlink:label="ifrs-full_CurrentAssets" xlink:type="locator"/>
      <link:loc xlink:href="81560001692D0424C949-2025-12-31.xsd#ext_SOMInventoryAndContractAssets" xlink:label="ext_SOMInventoryAndContractAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_CurrentAssets"
                          xlink:to="ext_SOMInventoryAndContractAssets"
                            weight="1.0"
                            order="1"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentTaxAssetsCurrent" xlink:label="ifrs-full_CurrentTaxAssetsCurrent" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_CurrentAssets"
                          xlink:to="ifrs-full_CurrentTaxAssetsCurrent"
                            weight="1.0"
                            order="2"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherCurrentFinancialAssets" xlink:label="ifrs-full_OtherCurrentFinancialAssets" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_CurrentAssets"
                          xlink:to="ifrs-full_OtherCurrentFinancialAssets"
                            weight="1.0"
                            order="3"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalents" xlink:label="ifrs-full_CashAndCashEquivalents" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_CurrentAssets"
                          xlink:to="ifrs-full_CashAndCashEquivalents"
                            weight="1.0"
                            order="4"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherCurrentReceivables" xlink:label="ifrs-full_OtherCurrentReceivables" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_CurrentAssets"
                          xlink:to="ifrs-full_OtherCurrentReceivables"
                            weight="1.0"
                            order="5"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentTradeReceivables" xlink:label="ifrs-full_CurrentTradeReceivables" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_CurrentAssets"
                          xlink:to="ifrs-full_CurrentTradeReceivables"
                            weight="1.0"
                            order="6"
                          xlink:type="arc"/>
   </link:calculationLink>
   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EquityAndLiabilities" xlink:label="ifrs-full_EquityAndLiabilities" xlink:type="locator"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Equity" xlink:label="ifrs-full_Equity" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_EquityAndLiabilities"
                          xlink:to="ifrs-full_Equity"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Liabilities" xlink:label="ifrs-full_Liabilities" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_EquityAndLiabilities"
                          xlink:to="ifrs-full_Liabilities"
                            order="20.0"
                            weight="1.0"
                          xlink:type="arc"/>
   </link:calculationLink>
   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Equity" xlink:label="ifrs-full_Equity" xlink:type="locator"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EquityAttributableToOwnersOfParent" xlink:label="ifrs-full_EquityAttributableToOwnersOfParent" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_Equity"
                          xlink:to="ifrs-full_EquityAttributableToOwnersOfParent"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncontrollingInterests" xlink:label="ifrs-full_NoncontrollingInterests" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_Equity"
                          xlink:to="ifrs-full_NoncontrollingInterests"
                            order="20.0"
                            weight="1.0"
                          xlink:type="arc"/>
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   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
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                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_EquityAttributableToOwnersOfParent"
                          xlink:to="ifrs-full_IssuedCapital"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SharePremium" xlink:label="ifrs-full_SharePremium" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_EquityAttributableToOwnersOfParent"
                          xlink:to="ifrs-full_SharePremium"
                            order="30.0"
                            weight="1.0"
                          xlink:type="arc"/>
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      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_EquityAttributableToOwnersOfParent"
                          xlink:to="ifrs-full_StatutoryReserve"
                            weight="1.0"
                            order="31.0"
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      <link:loc xlink:href="81560001692D0424C949-2025-12-31.xsd#ext_SOMRetainedEarningsAndOtherReserves" xlink:label="ext_SOMRetainedEarningsAndOtherReserves" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_EquityAttributableToOwnersOfParent"
                          xlink:to="ext_SOMRetainedEarningsAndOtherReserves"
                            weight="1.0"
                            order="32.0"
                          xlink:type="arc"/>
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   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
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      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_Liabilities"
                          xlink:to="ifrs-full_NoncurrentLiabilities"
                            order="10.0"
                            weight="1.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentLiabilities" xlink:label="ifrs-full_CurrentLiabilities" xlink:type="locator"/>
      <link:calculationArc
                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_Liabilities"
                          xlink:to="ifrs-full_CurrentLiabilities"
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                            weight="1.0"
                          xlink:type="arc"/>
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   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
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                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_OtherLongtermProvisions"
                            weight="1.0"
                            order="29.0"
                          xlink:type="arc"/>
      <link:loc xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxLiabilities" xlink:label="ifrs-full_DeferredTaxLiabilities" xlink:type="locator"/>
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                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_DeferredTaxLiabilities"
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                            weight="1.0"
                          xlink:type="arc"/>
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                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_CurrentTaxLiabilitiesNoncurrent"
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                            weight="1.0"
                          xlink:type="arc"/>
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                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_OtherNoncurrentNonfinancialLiabilities"
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                          xlink:type="arc"/>
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                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_LongtermBorrowings"
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                          xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item"
                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_OtherNoncurrentLiabilities"
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                            order="62.0"
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                          xlink:from="ifrs-full_NoncurrentLiabilities"
                          xlink:to="ifrs-full_RecognisedLiabilitiesDefinedBenefitPlan"
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                            order="63.0"
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   <link:calculationLink xlink:role="https://www.somecgroup.com/xbrl/role/all/ias_1_role-210000" xlink:type="extended">
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