posted by jp .
How do you find 81 - 16 using mental math?
I'd round the numbers to 80 - 15
Just do the problem in your head, don't use any outside sources like a calculator or a paper/pencil. I would also do like Ms. Sue said - round 81 to 80 and 16 to 15.
Your butt plus my bütt ID thesse nuts
Explain it tell how to find 81-16 using mental maht