Name
Chapter 3, Lesson 3
Reteach
Date
Estimate Sums
CA Standards
NS 1.3,
NS 3.0
You can use rounding to estimate sums.
Round to estimate the sum of 477 + 592.
Step 1 Round each addend to the nearest hundred.
477 rounds to 500.
592 rounds to 600.
Step 2 Add the rounded numbers. 500 + 600 = 1,100
Step 3 You can get a closer estimate by rounding to a lesser place value. Rounding
to the nearest ten gives you addends of 480 and 590. You can add these
numbers to find a sum of 1,070.
Solution: 477 + 592 is about 1,070.
Round each number to the nearest ten. Then estimate the sum.
1.
77 + 28 =
2.
66 + 31 =
3.
196 + 47 =
4.
4,042 + 683 =
8.
798 + 136 =
Round each number to the nearest hundred. Then estimate
the sum.
5.
429 + 518 =
6.
545 + 106 =
7.
273 + 322 =
Writing Math Explain how you could find a closer estimate
for problem 8.
Reteach
Use with text pages 58–60.
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