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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 532 · 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 84 × 97? (a) 8000 (b) 800 (c) 80000
  2. 2.Best estimate of 774 + 216? (a) 1000 (b) 1200 (c) 800
  3. 3.Best estimate of 88 × 51? (a) 4500 (b) 450 (c) 45000
  4. 4.Best estimate of 36 × 34? (a) 1200 (b) 12000 (c) 120
  5. 5.Best estimate of 615 + 778? (a) 1400 (b) 1200 (c) 1600
  6. 6.Best estimate of 78 × 34? (a) 24000 (b) 240 (c) 2400
  7. 7.Best estimate of 38 × 57? (a) 24000 (b) 240 (c) 2400
  8. 8.Best estimate of 20 × 42? (a) 800 (b) 8000 (c) 80
  9. 9.Best estimate of 24 × 32? (a) 6000 (b) 600 (c) 60
  10. 10.Best estimate of 27 × 82? (a) 240 (b) 24000 (c) 2400
  11. 11.Best estimate of 53 × 47? (a) 2500 (b) 25000 (c) 250
  12. 12.Best estimate of 51 × 76? (a) 40000 (b) 400 (c) 4000
  13. 13.Best estimate of 869 + 430? (a) 1100 (b) 1500 (c) 1300
  14. 14.Best estimate of 56 × 74? (a) 4200 (b) 420 (c) 42000
  15. 15.Best estimate of 389 + 527? (a) 900 (b) 1100 (c) 700
  16. 16.Best estimate of 13 × 41? (a) 40 (b) 400 (c) 4000
  17. 17.Best estimate of 599 + 584? (a) 1400 (b) 1200 (c) 1000
  18. 18.Best estimate of 260 + 196? (a) 500 (b) 700 (c) 300
  19. 19.Best estimate of 94 × 54? (a) 4500 (b) 45000 (c) 450
  20. 20.Best estimate of 470 + 751? (a) 1100 (b) 1500 (c) 1300
  21. 21.Best estimate of 216 + 160? (a) 400 (b) 600 (c) 200
  22. 22.Best estimate of 49 × 49? (a) 250 (b) 2500 (c) 25000
  23. 23.Best estimate of 22 × 31? (a) 6000 (b) 60 (c) 600
  24. 24.Best estimate of 21 × 42? (a) 80 (b) 8000 (c) 800
  25. 25.Best estimate of 23 × 17? (a) 4000 (b) 40 (c) 400
  26. 26.Best estimate of 682 + 447? (a) 900 (b) 1300 (c) 1100
  27. 27.Best estimate of 64 × 34? (a) 180 (b) 18000 (c) 1800
  28. 28.Best estimate of 26 × 29? (a) 9000 (b) 90 (c) 900
  29. 29.Best estimate of 30 × 76? (a) 2400 (b) 24000 (c) 240
  30. 30.Best estimate of 554 + 445? (a) 1000 (b) 1200 (c) 800
  31. 31.Best estimate of 178 + 712? (a) 1100 (b) 900 (c) 700
  32. 32.Best estimate of 426 + 197? (a) 800 (b) 600 (c) 400
  33. 33.Best estimate of 384 + 716? (a) 900 (b) 1100 (c) 1300
  34. 34.Best estimate of 54 × 53? (a) 25000 (b) 2500 (c) 250
  35. 35.Best estimate of 828 + 261? (a) 1100 (b) 900 (c) 1300
  36. 36.Best estimate of 505 + 677? (a) 1400 (b) 1200 (c) 1000
  37. 37.Best estimate of 823 + 523? (a) 1300 (b) 1500 (c) 1100
  38. 38.Best estimate of 46 × 74? (a) 350 (b) 35000 (c) 3500
  39. 39.Best estimate of 744 + 698? (a) 1200 (b) 1400 (c) 1600
  40. 40.Best estimate of 280 + 262? (a) 600 (b) 800 (c) 400

Answer key

  1. 8000
  2. 1000
  3. 4500
  4. 1200
  5. 1400
  6. 2400
  7. 2400
  8. 800
  9. 600
  10. 2400
  11. 2500
  12. 4000
  13. 1300
  14. 4200
  15. 900
  16. 400
  17. 1200
  18. 500
  19. 4500
  20. 1300
  21. 400
  22. 2500
  23. 600
  24. 800
  25. 400
  26. 1100
  27. 1800
  28. 900
  29. 2400
  30. 1000
  31. 900
  32. 600
  33. 1100
  34. 2500
  35. 1100
  36. 1200
  37. 1300
  38. 3500
  39. 1400
  40. 600

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