Estimating Sums and Differences of Mixed Numbers
When adding or subtracting mixed numbers, we can check by
estimating, determining whether our estimate and our answer are
close. Note that when we round mixed numbers, we round to the
nearest whole number.
Checking a Sum by Estimating
Checking a Difference by Estimating
EXAMPLE
Combine and check:
Solution
We begin by adding the first two mixed numbers:
Next, we subtract from this sum.
So .
Now let’s check this answer by estimation.
The estimate, 7, is sufficiently close to to confirm our answer.
