Functional Skills Mathematics
(Entry Level 2)
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Topic 6: Checking your answer


Addition (+) is the reverse of subtraction (-).
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3 + 2 = 5
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5 - 2 = 3
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Notice how the same three numbers are used, but in the reverse order. This fact is very useful for checking your answer when calculating.
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For example, you may perform the following subtraction:
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64 - 38 = 26
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To check that this is correct you can reverse the subtraction into an addition (which most people find easier than subtraction):
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26 + 38 = 64
If you end up with the same three numbers, but in reverse order, you can be confident your subtraction was correct.
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Multiplication (×) is the reverse of division (÷).
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5 × 2 = 10
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10 ÷ 2 = 5
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Notice how the same three numbers are used, but in the reverse order. This fact is very useful for checking your answer when calculating.
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For example, you may perform the following division:
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26 ÷ 2 = 13
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To check that this is correct you can reverse the division into a multiplication (which most people find easier than division):
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13 × 2 = 26