Rounding and Estimating Sums and Differences

Round: Nearest Ten

100

Round 32 to the nearest ten

30

200

Round 88 to the nearest ten

90

300

Round 47 to the nearest ten

50

400

Round 92 to the nearest ten

90

500

Round 98 to the nearest ten

100

Round: Nearest Hundred

100

Round 137 to the nearest hundred

100

200

Round 567 to the nearest hundred

600

300

Round 890 to the nearest hundred

900

400

Round 502 to the nearest hundred

500

500

Round 850 to the nearest hundred

900

Estimate with addition (to nearest hundred)

100

Estimate by rounding to the nearest hundred: 

452 + 312

500 + 300 = about 800

200

Estimate the sum by rounding to the nearest hundred:

425 + 268

400 + 300 = About 700

300

Estimate the sum by rounding to the nearest hundred:

679 + 215

700 + 200 = About 900

400

Estimate the sum by rounding to the nearest hundred:

736 + 242

700 + 200 = About 900

500

Estimate the sum by rounding to the nearest hundred: 

477 + 523

500 + 500 = about 1,000

Estimate with addition (to nearest ten)

100

Estimate the sum by rounding to the nearest ten:

47 + 52

50 + 50 = about 100

200

Estimate the sum by rounding to the nearest ten:

12 + 83

10 + 80 = About 90

300

Estimate the sum by rounding to the nearest ten:

39 + 19

40 + 20 = About 60

400

Estimate the sum by rounding to the nearest ten:

44 + 82

40 + 80 = About 120

500

Estimate the sum by rounding to the nearest ten:

93 + 24

90 + 20 = About 110

Exact Addition

100

512 + 423

935

200

543 + 236

779

300

368 + 124

492

400

459 + 173

632

500

274 + 856

1130