compensate

Compensation is a method or strategy used in mental arithmetic or paper and pen calculation.

In order to simplify the process, we round off one of the numbers in a calculation.

For example, 36 + 18 is rounded to 36 + 20 which gives a total of 56. Then, we adapt the answer by subtracting 2 in order to get the answer to the original calculation, which is 54.

As well as subtracting a number, it’s possible to add a number. If we round a number to a lower value, we have to compensate by adding a number.

For example, 87 – 39 is rounded to 87 – 40 which gives a total of 47. Then, we adapt the answer by adding 1 in order to get the answer to the original calculation, which is 48.