Grade 4 - Progress in Mathematics

Estimate Sums and Differences

2-7

Rounding is one way to estimate

sums and differences.

• Round each number to the
  greatest place of the least number.


• Add or subtract the rounded numbers.

Estimate: 4360 
 654 
 1207 Estimate: 186,491 44,786

4360 4400 186,491 19 0,000

654 700  44,786  4 0,000


 1207 
 1200 about 15 0,000

about 6300

Study these examples.

Round to dollars.

$56.39 $ 56 .00 208,124 2 00,000

 4.25  4 .00 
632,575 
 6 00,000

about $ 52 .00 about 8 00,000

Round to hundreds. Round to ten thousands.

Round to hundred thousands.

Estimate each sum by rounding.

1. $.25 2. 53 3. 632 4. $5.25 5. $37.47
   
   .14
   76
   149
   2.30
   42.58
   about $.40


2. 1432 7. 7859 8. $17.89 9. 22,165 10. 426,031
   4290 523 4.56 56,972 109,764
   
   3671
   1324
   10.32
   4,065
   362,801


3. 314,402
   23,067 12. 534
   2414
   876 13. 642,118
   153,062

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