Writing to Explain Use rounding to estimate the product 12*9. Then, use compensation to find the total cost for 12 books that were $9 each, would she get a good estimate? Explain

So if we do not know what 12 times 9 is then we can round 9 to 10 and get

12 times 10

most people can multiply by ten so this should be easy so

12 times 10=120

12 times 9=108

she was off by 12 so a 10% deviation error

another way to do it is you multiply 12 by 10 and get 10 12's

then you subtract 1 12 and get 9 12's