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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 899 · 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 × 63? (a) 54000 (b) 5400 (c) 540
  2. 2.Best estimate of 268 + 153? (a) 300 (b) 500 (c) 700
  3. 3.Best estimate of 641 + 199? (a) 800 (b) 600 (c) 1000
  4. 4.Best estimate of 76 × 79? (a) 64000 (b) 6400 (c) 640
  5. 5.Best estimate of 290 + 606? (a) 900 (b) 1100 (c) 700
  6. 6.Best estimate of 863 + 752? (a) 1900 (b) 1500 (c) 1700
  7. 7.Best estimate of 71 × 50? (a) 3500 (b) 35000 (c) 350
  8. 8.Best estimate of 53 × 96? (a) 5000 (b) 50000 (c) 500
  9. 9.Best estimate of 72 × 27? (a) 2100 (b) 210 (c) 21000
  10. 10.Best estimate of 63 × 49? (a) 3000 (b) 30000 (c) 300
  11. 11.Best estimate of 279 + 181? (a) 300 (b) 700 (c) 500
  12. 12.Best estimate of 634 + 285? (a) 1100 (b) 700 (c) 900
  13. 13.Best estimate of 136 + 300? (a) 400 (b) 600 (c) 200
  14. 14.Best estimate of 63 × 16? (a) 1200 (b) 120 (c) 12000
  15. 15.Best estimate of 18 × 60? (a) 1200 (b) 120 (c) 12000
  16. 16.Best estimate of 72 × 34? (a) 210 (b) 2100 (c) 21000
  17. 17.Best estimate of 628 + 856? (a) 1300 (b) 1700 (c) 1500
  18. 18.Best estimate of 149 + 796? (a) 900 (b) 700 (c) 1100
  19. 19.Best estimate of 94 × 21? (a) 18000 (b) 180 (c) 1800
  20. 20.Best estimate of 482 + 782? (a) 1300 (b) 1500 (c) 1100
  21. 21.Best estimate of 96 × 63? (a) 6000 (b) 60000 (c) 600
  22. 22.Best estimate of 516 + 325? (a) 1000 (b) 800 (c) 600
  23. 23.Best estimate of 697 + 568? (a) 1500 (b) 1300 (c) 1100
  24. 24.Best estimate of 73 × 86? (a) 630 (b) 63000 (c) 6300
  25. 25.Best estimate of 51 × 56? (a) 3000 (b) 30000 (c) 300
  26. 26.Best estimate of 23 × 14? (a) 200 (b) 2000 (c) 20
  27. 27.Best estimate of 14 × 22? (a) 20 (b) 200 (c) 2000
  28. 28.Best estimate of 182 + 320? (a) 700 (b) 300 (c) 500
  29. 29.Best estimate of 720 + 460? (a) 1200 (b) 1400 (c) 1000
  30. 30.Best estimate of 37 × 47? (a) 2000 (b) 200 (c) 20000
  31. 31.Best estimate of 96 × 66? (a) 7000 (b) 70000 (c) 700
  32. 32.Best estimate of 411 + 356? (a) 1000 (b) 600 (c) 800
  33. 33.Best estimate of 40 × 96? (a) 400 (b) 4000 (c) 40000
  34. 34.Best estimate of 849 + 853? (a) 1900 (b) 1500 (c) 1700
  35. 35.Best estimate of 297 + 876? (a) 1200 (b) 1400 (c) 1000
  36. 36.Best estimate of 66 × 16? (a) 14000 (b) 140 (c) 1400
  37. 37.Best estimate of 27 × 61? (a) 18000 (b) 1800 (c) 180
  38. 38.Best estimate of 49 × 86? (a) 450 (b) 4500 (c) 45000
  39. 39.Best estimate of 40 × 13? (a) 40 (b) 400 (c) 4000
  40. 40.Best estimate of 18 × 76? (a) 1600 (b) 160 (c) 16000

Answer key

  1. 5400
  2. 500
  3. 800
  4. 6400
  5. 900
  6. 1700
  7. 3500
  8. 5000
  9. 2100
  10. 3000
  11. 500
  12. 900
  13. 400
  14. 1200
  15. 1200
  16. 2100
  17. 1500
  18. 900
  19. 1800
  20. 1300
  21. 6000
  22. 800
  23. 1300
  24. 6300
  25. 3000
  26. 200
  27. 200
  28. 500
  29. 1200
  30. 2000
  31. 7000
  32. 800
  33. 4000
  34. 1700
  35. 1200
  36. 1400
  37. 1800
  38. 4500
  39. 400
  40. 1600

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