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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 726 · 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 37 × 34? (a) 120 (b) 12000 (c) 1200
  2. 2.Best estimate of 387 + 875? (a) 1500 (b) 1100 (c) 1300
  3. 3.Best estimate of 387 + 186? (a) 400 (b) 800 (c) 600
  4. 4.Best estimate of 327 + 860? (a) 1400 (b) 1000 (c) 1200
  5. 5.Best estimate of 292 + 484? (a) 600 (b) 800 (c) 1000
  6. 6.Best estimate of 61 × 16? (a) 1200 (b) 120 (c) 12000
  7. 7.Best estimate of 546 + 721? (a) 1000 (b) 1200 (c) 1400
  8. 8.Best estimate of 62 × 68? (a) 4200 (b) 420 (c) 42000
  9. 9.Best estimate of 26 × 26? (a) 900 (b) 9000 (c) 90
  10. 10.Best estimate of 416 + 701? (a) 900 (b) 1100 (c) 1300
  11. 11.Best estimate of 281 + 238? (a) 700 (b) 500 (c) 300
  12. 12.Best estimate of 381 + 521? (a) 700 (b) 900 (c) 1100
  13. 13.Best estimate of 79 × 66? (a) 56000 (b) 5600 (c) 560
  14. 14.Best estimate of 278 + 317? (a) 400 (b) 600 (c) 800
  15. 15.Best estimate of 39 × 42? (a) 1600 (b) 160 (c) 16000
  16. 16.Best estimate of 473 + 268? (a) 600 (b) 1000 (c) 800
  17. 17.Best estimate of 91 × 32? (a) 2700 (b) 270 (c) 27000
  18. 18.Best estimate of 44 × 16? (a) 8000 (b) 800 (c) 80
  19. 19.Best estimate of 97 × 89? (a) 90000 (b) 900 (c) 9000
  20. 20.Best estimate of 557 + 385? (a) 1200 (b) 800 (c) 1000
  21. 21.Best estimate of 59 × 76? (a) 48000 (b) 4800 (c) 480
  22. 22.Best estimate of 49 × 50? (a) 2500 (b) 25000 (c) 250
  23. 23.Best estimate of 73 × 62? (a) 42000 (b) 4200 (c) 420
  24. 24.Best estimate of 439 + 506? (a) 900 (b) 700 (c) 1100
  25. 25.Best estimate of 765 + 786? (a) 1600 (b) 1800 (c) 1400
  26. 26.Best estimate of 52 × 30? (a) 150 (b) 1500 (c) 15000
  27. 27.Best estimate of 12 × 32? (a) 300 (b) 30 (c) 3000
  28. 28.Best estimate of 40 × 62? (a) 2400 (b) 240 (c) 24000
  29. 29.Best estimate of 766 + 148? (a) 900 (b) 700 (c) 1100
  30. 30.Best estimate of 851 + 826? (a) 1700 (b) 1900 (c) 1500
  31. 31.Best estimate of 763 + 221? (a) 1200 (b) 1000 (c) 800
  32. 32.Best estimate of 191 + 284? (a) 700 (b) 500 (c) 300
  33. 33.Best estimate of 26 × 56? (a) 1800 (b) 180 (c) 18000
  34. 34.Best estimate of 62 × 89? (a) 54000 (b) 5400 (c) 540
  35. 35.Best estimate of 68 × 97? (a) 7000 (b) 700 (c) 70000
  36. 36.Best estimate of 81 × 89? (a) 72000 (b) 7200 (c) 720
  37. 37.Best estimate of 225 + 549? (a) 500 (b) 900 (c) 700
  38. 38.Best estimate of 444 + 733? (a) 1300 (b) 1100 (c) 900
  39. 39.Best estimate of 36 × 31? (a) 1200 (b) 12000 (c) 120
  40. 40.Best estimate of 329 + 517? (a) 1000 (b) 800 (c) 600

Answer key

  1. 1200
  2. 1300
  3. 600
  4. 1200
  5. 800
  6. 1200
  7. 1200
  8. 4200
  9. 900
  10. 1100
  11. 500
  12. 900
  13. 5600
  14. 600
  15. 1600
  16. 800
  17. 2700
  18. 800
  19. 9000
  20. 1000
  21. 4800
  22. 2500
  23. 4200
  24. 900
  25. 1600
  26. 1500
  27. 300
  28. 2400
  29. 900
  30. 1700
  31. 1000
  32. 500
  33. 1800
  34. 5400
  35. 7000
  36. 7200
  37. 700
  38. 1100
  39. 1200
  40. 800

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