Golden Rule: Always work out minutes and hours separately.
Addition: Add minutes with minutes, add hours with hours. Rename if minutes are bigger than 60
Subtraction: Subtract minutes from minutes first. If minutes on top are smaller, rename. You do this by taking 1 hour from hours. This becomes 60 minutes, add it to minutes on top. Proceed with the sum.
Multiplication: Multiply minutes first. Rename if bigger than 60 minutes. Multiply hours making sure to include renamed hours from minutes if they are there.
Division: Divide hours first. If there is remainder 1, that is one hour, so you add 60 minutes to minutes section. If there is remainder 2, that is 2 hours, so you add 120 minutes to minutes section etc. Proceed to divide minutes making sure you have added on remainders from hours.
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