They are 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 multiplying 11 and 4 to get 44 and add three zeros at the end to get 44000.

Have you ever wished you could divide numbers quickly and easily in your head? Believe it or not, you can. Check out these 5 tips that will help you become a mental division maestro shared by *Quickanddirtytips.com*.