Estimating Products and Quotients of Mixed Numbers
As with adding or subtracting mixed numbers, it is important
to check our answers when multiplying or dividing. We can check a
product or a quotient of mixed numbers by estimating the answer
and then confirming that our estimate and answer are reasonably
close.
Checking a Product by Estimating
Because is near 16, is a reasonable answer.
Checking a Quotient by Estimating
Because 2 is near , is a reasonable answer.
EXAMPLE
Simplify and check:
Solution
Following the order of operations rule, we work from left to
right, multiplying the first two mixed numbers.
Then we divide 20 by to get the answer.
Now let’s check by estimation.
Our answer, , and our estimate, 7, are reasonably
close, confirming the answer.
