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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 723 · 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 502 + 479? (a) 800 (b) 1200 (c) 1000
  2. 2.Best estimate of 440 + 264? (a) 500 (b) 700 (c) 900
  3. 3.Best estimate of 877 + 510? (a) 1400 (b) 1600 (c) 1200
  4. 4.Best estimate of 64 × 96? (a) 6000 (b) 60000 (c) 600
  5. 5.Best estimate of 237 + 207? (a) 400 (b) 200 (c) 600
  6. 6.Best estimate of 54 × 36? (a) 20000 (b) 200 (c) 2000
  7. 7.Best estimate of 31 × 83? (a) 240 (b) 24000 (c) 2400
  8. 8.Best estimate of 96 × 27? (a) 30000 (b) 300 (c) 3000
  9. 9.Best estimate of 846 + 347? (a) 1300 (b) 900 (c) 1100
  10. 10.Best estimate of 18 × 12? (a) 20 (b) 200 (c) 2000
  11. 11.Best estimate of 92 × 60? (a) 5400 (b) 540 (c) 54000
  12. 12.Best estimate of 26 × 52? (a) 1500 (b) 150 (c) 15000
  13. 13.Best estimate of 528 + 161? (a) 900 (b) 500 (c) 700
  14. 14.Best estimate of 19 × 57? (a) 120 (b) 1200 (c) 12000
  15. 15.Best estimate of 200 + 271? (a) 300 (b) 500 (c) 700
  16. 16.Best estimate of 77 × 79? (a) 6400 (b) 64000 (c) 640
  17. 17.Best estimate of 86 × 27? (a) 27000 (b) 2700 (c) 270
  18. 18.Best estimate of 389 + 686? (a) 900 (b) 1300 (c) 1100
  19. 19.Best estimate of 87 × 48? (a) 45000 (b) 4500 (c) 450
  20. 20.Best estimate of 147 + 462? (a) 600 (b) 400 (c) 800
  21. 21.Best estimate of 236 + 615? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 564 + 819? (a) 1600 (b) 1200 (c) 1400
  23. 23.Best estimate of 575 + 567? (a) 1400 (b) 1000 (c) 1200
  24. 24.Best estimate of 83 × 41? (a) 3200 (b) 32000 (c) 320
  25. 25.Best estimate of 71 × 66? (a) 4900 (b) 49000 (c) 490
  26. 26.Best estimate of 445 + 268? (a) 700 (b) 900 (c) 500
  27. 27.Best estimate of 30 × 36? (a) 12000 (b) 120 (c) 1200
  28. 28.Best estimate of 64 × 44? (a) 24000 (b) 2400 (c) 240
  29. 29.Best estimate of 779 + 211? (a) 1000 (b) 1200 (c) 800
  30. 30.Best estimate of 96 × 80? (a) 800 (b) 80000 (c) 8000
  31. 31.Best estimate of 17 × 33? (a) 600 (b) 6000 (c) 60
  32. 32.Best estimate of 818 + 660? (a) 1500 (b) 1300 (c) 1700
  33. 33.Best estimate of 253 + 876? (a) 1200 (b) 1400 (c) 1000
  34. 34.Best estimate of 548 + 462? (a) 1200 (b) 800 (c) 1000
  35. 35.Best estimate of 19 × 73? (a) 140 (b) 1400 (c) 14000
  36. 36.Best estimate of 59 × 33? (a) 1800 (b) 18000 (c) 180
  37. 37.Best estimate of 76 × 98? (a) 800 (b) 8000 (c) 80000
  38. 38.Best estimate of 83 × 28? (a) 240 (b) 2400 (c) 24000
  39. 39.Best estimate of 300 + 219? (a) 700 (b) 300 (c) 500
  40. 40.Best estimate of 27 × 41? (a) 120 (b) 12000 (c) 1200

Answer key

  1. 1000
  2. 700
  3. 1400
  4. 6000
  5. 400
  6. 2000
  7. 2400
  8. 3000
  9. 1100
  10. 200
  11. 5400
  12. 1500
  13. 700
  14. 1200
  15. 500
  16. 6400
  17. 2700
  18. 1100
  19. 4500
  20. 600
  21. 800
  22. 1400
  23. 1200
  24. 3200
  25. 4900
  26. 700
  27. 1200
  28. 2400
  29. 1000
  30. 8000
  31. 600
  32. 1500
  33. 1200
  34. 1000
  35. 1400
  36. 1800
  37. 8000
  38. 2400
  39. 500
  40. 1200

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