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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 78 · 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 478 + 682? (a) 1400 (b) 1200 (c) 1000
  2. 2.Best estimate of 551 + 412? (a) 1000 (b) 1200 (c) 800
  3. 3.Best estimate of 644 + 172? (a) 600 (b) 1000 (c) 800
  4. 4.Best estimate of 512 + 689? (a) 1200 (b) 1000 (c) 1400
  5. 5.Best estimate of 96 × 87? (a) 900 (b) 90000 (c) 9000
  6. 6.Best estimate of 172 + 298? (a) 300 (b) 500 (c) 700
  7. 7.Best estimate of 273 + 310? (a) 600 (b) 800 (c) 400
  8. 8.Best estimate of 178 + 329? (a) 700 (b) 300 (c) 500
  9. 9.Best estimate of 419 + 726? (a) 1100 (b) 1300 (c) 900
  10. 10.Best estimate of 639 + 396? (a) 800 (b) 1000 (c) 1200
  11. 11.Best estimate of 93 × 82? (a) 720 (b) 72000 (c) 7200
  12. 12.Best estimate of 64 × 17? (a) 12000 (b) 120 (c) 1200
  13. 13.Best estimate of 791 + 795? (a) 1600 (b) 1400 (c) 1800
  14. 14.Best estimate of 96 × 77? (a) 8000 (b) 80000 (c) 800
  15. 15.Best estimate of 37 × 76? (a) 320 (b) 32000 (c) 3200
  16. 16.Best estimate of 83 × 74? (a) 56000 (b) 560 (c) 5600
  17. 17.Best estimate of 82 × 38? (a) 320 (b) 3200 (c) 32000
  18. 18.Best estimate of 39 × 12? (a) 40 (b) 400 (c) 4000
  19. 19.Best estimate of 540 + 186? (a) 700 (b) 500 (c) 900
  20. 20.Best estimate of 41 × 59? (a) 240 (b) 2400 (c) 24000
  21. 21.Best estimate of 16 × 79? (a) 160 (b) 16000 (c) 1600
  22. 22.Best estimate of 32 × 22? (a) 6000 (b) 600 (c) 60
  23. 23.Best estimate of 184 + 743? (a) 1100 (b) 700 (c) 900
  24. 24.Best estimate of 257 + 676? (a) 1200 (b) 1000 (c) 800
  25. 25.Best estimate of 91 × 62? (a) 540 (b) 5400 (c) 54000
  26. 26.Best estimate of 12 × 88? (a) 90 (b) 900 (c) 9000
  27. 27.Best estimate of 67 × 56? (a) 42000 (b) 420 (c) 4200
  28. 28.Best estimate of 363 + 654? (a) 1100 (b) 900 (c) 1300
  29. 29.Best estimate of 286 + 710? (a) 1000 (b) 800 (c) 1200
  30. 30.Best estimate of 61 × 13? (a) 6000 (b) 600 (c) 60
  31. 31.Best estimate of 244 + 338? (a) 300 (b) 700 (c) 500
  32. 32.Best estimate of 81 × 97? (a) 80000 (b) 800 (c) 8000
  33. 33.Best estimate of 863 + 271? (a) 1400 (b) 1200 (c) 1000
  34. 34.Best estimate of 19 × 92? (a) 18000 (b) 180 (c) 1800
  35. 35.Best estimate of 77 × 69? (a) 5600 (b) 56000 (c) 560
  36. 36.Best estimate of 712 + 333? (a) 1000 (b) 800 (c) 1200
  37. 37.Best estimate of 39 × 21? (a) 80 (b) 800 (c) 8000
  38. 38.Best estimate of 190 + 473? (a) 700 (b) 900 (c) 500
  39. 39.Best estimate of 511 + 590? (a) 1100 (b) 1300 (c) 900
  40. 40.Best estimate of 32 × 32? (a) 90 (b) 9000 (c) 900

Answer key

  1. 1200
  2. 1000
  3. 800
  4. 1200
  5. 9000
  6. 500
  7. 600
  8. 500
  9. 1100
  10. 1000
  11. 7200
  12. 1200
  13. 1600
  14. 8000
  15. 3200
  16. 5600
  17. 3200
  18. 400
  19. 700
  20. 2400
  21. 1600
  22. 600
  23. 900
  24. 1000
  25. 5400
  26. 900
  27. 4200
  28. 1100
  29. 1000
  30. 600
  31. 500
  32. 8000
  33. 1200
  34. 1800
  35. 5600
  36. 1000
  37. 800
  38. 700
  39. 1100
  40. 900

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