Posted by **jp** on Wednesday, November 14, 2012 at 6:47pm.

How do you find 81 - 16 using mental math?

- subtraction (math) -
**Ms. Sue**, Wednesday, November 14, 2012 at 6:54pm
I'd round the numbers to 80 - 15

- subtraction (math) -
**Delilah**, Thursday, November 15, 2012 at 6:55pm
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.

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