10 A quick reminder: checking your work

Next you can take a quiz to review what you have learned in this session. For this and later quizzes in the course you should check your answers. A check is an alternative method or reverse calculation – you may have heard this being called an inverse calculation. If the check results in a correct answer, it means that your original sum is correct too. For example, you may have made the following calculation:

• 20 – 8 = 12

A way of checking this would be:

• 12 + 8 = 20

Alternatively, if you wanted to check the following calculation:

• 80 × 2 = 160

A way of checking this would be:

• 160 ÷ 2 = 80

If you have carried out several calculations to get to your final answer, you only need to reverse one as a check.