Numbers that are easy to divide mentally are called what?

It is called compatible numbers.

Compatible numbers are numbers that look nice or friendly with each other when we do mental calculation to estimate a product, but especially a division.

Some examples of compatible numbers when doing division are 400 and 10, 36 and 6, 2400 and 12, and 64 and 8:

  • 2400 and 12 are compatible because when doing this division (2400/12), we can quickly divide 24 by 12 to get 2 and put two zeros at the end to get 200

Some examples of compatible numbers when doing multiplication are 200 and 40, 1100 and 40, 25 and 4:

  • 1100 and 40 are compatible because we can quickly do this multiplication by multipling 11 and 4 to get 44 and add three zeros at the end to get 44000.

Tip! If you're trying to find the percent of a number, it may be helpful to use compatible numbers to find an estimated answer. Follow along with this tutorial to see how to use compatible numbers to estimate the percent of a number from Virtualnerd.com.

Updated on Tuesday, August 25 2015 at 12:32PM EDT