In most cases the Canada Revenue Agency (CRA) will explain how they calculated the amount of your refund/balance owing. You will find this information on your Notice of Assessment (NoA). You can compare the line numbers on your NoA with your tax return to see what the CRA changed.
The reasons for the discrepancies may be different - e.g. typo, forgotten slip, etc.
If there is a difference between calculations you can complete the following: How do I submit a claim under the TurboTax 100% Accurate Calculations Guarantee?
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