Compatible Numbers

I know there have been a lot of questions about compatible numbers. I hope this will help you out. Please let me know if you have any other questions.

Definition of Compatible Number

·         Compatible numbers are numbers that are close in value to the actual numbers and easy to add, subtract, multiply, or divide mentally.

·         They are useful in estimating the sum, difference, product, or quotient.

Example 422 + 38

Compatible numbers usually end in 0 or 5.

420 + 40 = 460  or

425 + 40 = 465 or

425 + 35 = 460

These would all be acceptable answers.

118-42

Compatible number examples:

120 – 40 =

The purpose is to make it easier when adding, subtracting, multiplying or dividing.