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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 292 · 40 questions
TalentJR

How to do it in your head (Round, then work): Round each number: 2-digit numbers to the nearest ten, 3-digit numbers to the nearest hundred. Do the easy sum with the round numbers. Choose the option closest to your estimate.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 88 × 28? (a) 2700 (b) 27000 (c) 270
  2. 2.Best estimate of 168 + 537? (a) 900 (b) 500 (c) 700
  3. 3.Best estimate of 661 + 490? (a) 1200 (b) 1400 (c) 1000
  4. 4.Best estimate of 222 + 680? (a) 1100 (b) 900 (c) 700
  5. 5.Best estimate of 98 × 92? (a) 9000 (b) 90000 (c) 900
  6. 6.Best estimate of 638 + 583? (a) 1200 (b) 1000 (c) 1400
  7. 7.Best estimate of 814 + 679? (a) 1300 (b) 1500 (c) 1700
  8. 8.Best estimate of 49 × 48? (a) 250 (b) 2500 (c) 25000
  9. 9.Best estimate of 68 × 41? (a) 2800 (b) 280 (c) 28000
  10. 10.Best estimate of 87 × 64? (a) 540 (b) 54000 (c) 5400
  11. 11.Best estimate of 587 + 659? (a) 1500 (b) 1300 (c) 1100
  12. 12.Best estimate of 39 × 68? (a) 28000 (b) 2800 (c) 280
  13. 13.Best estimate of 627 + 176? (a) 600 (b) 1000 (c) 800
  14. 14.Best estimate of 783 + 701? (a) 1500 (b) 1700 (c) 1300
  15. 15.Best estimate of 30 × 41? (a) 1200 (b) 12000 (c) 120
  16. 16.Best estimate of 259 + 721? (a) 1000 (b) 800 (c) 1200
  17. 17.Best estimate of 26 × 96? (a) 3000 (b) 300 (c) 30000
  18. 18.Best estimate of 36 × 58? (a) 24000 (b) 2400 (c) 240
  19. 19.Best estimate of 17 × 50? (a) 1000 (b) 100 (c) 10000
  20. 20.Best estimate of 170 + 853? (a) 1300 (b) 1100 (c) 900
  21. 21.Best estimate of 228 + 804? (a) 1200 (b) 1000 (c) 800
  22. 22.Best estimate of 81 × 81? (a) 64000 (b) 640 (c) 6400
  23. 23.Best estimate of 254 + 876? (a) 1400 (b) 1200 (c) 1000
  24. 24.Best estimate of 64 × 22? (a) 1200 (b) 120 (c) 12000
  25. 25.Best estimate of 50 × 32? (a) 15000 (b) 1500 (c) 150
  26. 26.Best estimate of 862 + 399? (a) 1300 (b) 1500 (c) 1100
  27. 27.Best estimate of 94 × 30? (a) 2700 (b) 270 (c) 27000
  28. 28.Best estimate of 86 × 74? (a) 6300 (b) 63000 (c) 630
  29. 29.Best estimate of 72 × 13? (a) 7000 (b) 70 (c) 700
  30. 30.Best estimate of 32 × 68? (a) 2100 (b) 21000 (c) 210
  31. 31.Best estimate of 96 × 50? (a) 5000 (b) 50000 (c) 500
  32. 32.Best estimate of 39 × 69? (a) 280 (b) 2800 (c) 28000
  33. 33.Best estimate of 17 × 79? (a) 16000 (b) 1600 (c) 160
  34. 34.Best estimate of 660 + 672? (a) 1200 (b) 1600 (c) 1400
  35. 35.Best estimate of 445 + 301? (a) 900 (b) 500 (c) 700
  36. 36.Best estimate of 553 + 807? (a) 1200 (b) 1600 (c) 1400
  37. 37.Best estimate of 440 + 708? (a) 1300 (b) 1100 (c) 900
  38. 38.Best estimate of 227 + 179? (a) 400 (b) 600 (c) 200
  39. 39.Best estimate of 89 × 47? (a) 45000 (b) 4500 (c) 450
  40. 40.Best estimate of 28 × 17? (a) 600 (b) 6000 (c) 60

Answer key

  1. 2700
  2. 700
  3. 1200
  4. 900
  5. 9000
  6. 1200
  7. 1500
  8. 2500
  9. 2800
  10. 5400
  11. 1300
  12. 2800
  13. 800
  14. 1500
  15. 1200
  16. 1000
  17. 3000
  18. 2400
  19. 1000
  20. 1100
  21. 1000
  22. 6400
  23. 1200
  24. 1200
  25. 1500
  26. 1300
  27. 2700
  28. 6300
  29. 700
  30. 2100
  31. 5000
  32. 2800
  33. 1600
  34. 1400
  35. 700
  36. 1400
  37. 1100
  38. 400
  39. 4500
  40. 600

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