Estimation and Rounding worksheet for practicing rounding numbers to the nearest ten and estimating sums and differences.

Let’s solve each part step by step.

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Part 1: Round to the nearest ten

We look at the ones digit:
- If it’s 5 or more, round up.
- If it’s less than 5, round down.

21 → ones digit is 1 → round down → 20
85 → ones digit is 5 → round up → 90
72 → ones digit is 2 → round down → 70

451 → ones digit is 1 → round down → 450
409 → ones digit is 9 → round up → 410
434 → ones digit is 4 → round down → 430

173 → ones digit is 3 → round down → 170
585 → ones digit is 5 → round up → 590
328 → ones digit is 8 → round up → 330

1,214 → ones digit is 4 → round down → 1,210
2,357 → ones digit is 7 → round up → 2,360
3,286 → ones digit is 6 → round up → 3,290

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Part 2: Estimate sum or difference by rounding to nearest ten

We’ll round each number first, then add or subtract.

Problem 1: 184 + 152
184 → round to 180 (ones digit 4)
152 → round to 150 (ones digit 2)
180 + 150 = 330

Problem 2: 276 - 173
276 → round to 280 (ones digit 6)
173 → round to 170 (ones digit 3)
280 - 170 = 110

Problem 3: 350 + 116
350 → already ends in 0 → stays 350
116 → round to 120 (ones digit 6)
350 + 120 = 470

Problem 4: 548 + 224
548 → round to 550 (ones digit 8)
224 → round to 220 (ones digit 4)
550 + 220 = 770

Problem 5: 673 - 148
673 → round to 670 (ones digit 3)
148 → round to 150 (ones digit 8)
670 - 150 = 520

Problem 6: 436 - 132
436 → round to 440 (ones digit 6)
132 → round to 130 (ones digit 2)
440 - 130 = 310

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Final Answer:

Round to the nearest ten:
21 → 20
85 → 90
72 → 70
451 → 450
409 → 410
434 → 430
173 → 170
585 → 590
328 → 330
1,214 → 1,210
2,357 → 2,360
3,286 → 3,290

Estimate sums/differences:
184 + 152 → 180 + 150 = 330
276 - 173 → 280 - 170 = 110
350 + 116 → 350 + 120 = 470
548 + 224 → 550 + 220 = 770
673 - 148 → 670 - 150 = 520
436 - 132 → 440 - 130 = 310