1. Estimating Sums and Differences of Fractions and Mixed Numbers

2. Benchmark Numbers
A benchmark is a number that is easy to use when you estimate. When estimating the sums and differences of fractions, we use the benchmarks 0, ½, and 1.

3. ½ ½ 3 5 + 11 25 + = Change each fraction to 0, ½, or 1.
Add or subtract. 3 5 + 11 25 + =

4. Example 2 7 4 + 9 15 = 1 +

5. Estimating Mixed Numbers
If you have mixed numbers, then round to the nearest whole number.
If the fraction is ½ or greater, then round up to the next number.
If it is less than ½, then round down to the whole number.

6. Example 15 3 10 1 4 8 10 6 16 =

7. Practice Estimate the following sums or differences 10 + 7 4) 1 + 5)
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