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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 789 · 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 46 × 92? (a) 45000 (b) 4500 (c) 450
  2. 2.Best estimate of 16 × 57? (a) 12000 (b) 1200 (c) 120
  3. 3.Best estimate of 92 × 70? (a) 63000 (b) 630 (c) 6300
  4. 4.Best estimate of 34 × 77? (a) 24000 (b) 2400 (c) 240
  5. 5.Best estimate of 14 × 86? (a) 90 (b) 900 (c) 9000
  6. 6.Best estimate of 51 × 71? (a) 350 (b) 35000 (c) 3500
  7. 7.Best estimate of 13 × 47? (a) 50 (b) 500 (c) 5000
  8. 8.Best estimate of 776 + 424? (a) 1400 (b) 1200 (c) 1000
  9. 9.Best estimate of 88 × 32? (a) 270 (b) 27000 (c) 2700
  10. 10.Best estimate of 660 + 260? (a) 800 (b) 1000 (c) 1200
  11. 11.Best estimate of 307 + 371? (a) 500 (b) 900 (c) 700
  12. 12.Best estimate of 562 + 659? (a) 1100 (b) 1300 (c) 1500
  13. 13.Best estimate of 39 × 53? (a) 20000 (b) 2000 (c) 200
  14. 14.Best estimate of 333 + 251? (a) 600 (b) 400 (c) 800
  15. 15.Best estimate of 50 × 59? (a) 30000 (b) 300 (c) 3000
  16. 16.Best estimate of 285 + 481? (a) 800 (b) 1000 (c) 600
  17. 17.Best estimate of 522 + 399? (a) 700 (b) 1100 (c) 900
  18. 18.Best estimate of 770 + 430? (a) 1400 (b) 1200 (c) 1000
  19. 19.Best estimate of 292 + 864? (a) 1200 (b) 1000 (c) 1400
  20. 20.Best estimate of 79 × 24? (a) 1600 (b) 160 (c) 16000
  21. 21.Best estimate of 17 × 94? (a) 180 (b) 18000 (c) 1800
  22. 22.Best estimate of 56 × 20? (a) 1200 (b) 120 (c) 12000
  23. 23.Best estimate of 267 + 177? (a) 500 (b) 700 (c) 300
  24. 24.Best estimate of 13 × 89? (a) 90 (b) 900 (c) 9000
  25. 25.Best estimate of 481 + 148? (a) 600 (b) 400 (c) 800
  26. 26.Best estimate of 310 + 712? (a) 800 (b) 1000 (c) 1200
  27. 27.Best estimate of 63 × 88? (a) 5400 (b) 54000 (c) 540
  28. 28.Best estimate of 478 + 208? (a) 500 (b) 700 (c) 900
  29. 29.Best estimate of 572 + 396? (a) 1000 (b) 1200 (c) 800
  30. 30.Best estimate of 21 × 28? (a) 600 (b) 6000 (c) 60
  31. 31.Best estimate of 867 + 341? (a) 1000 (b) 1400 (c) 1200
  32. 32.Best estimate of 96 × 82? (a) 800 (b) 8000 (c) 80000
  33. 33.Best estimate of 688 + 396? (a) 1100 (b) 900 (c) 1300
  34. 34.Best estimate of 43 × 24? (a) 8000 (b) 80 (c) 800
  35. 35.Best estimate of 21 × 51? (a) 10000 (b) 1000 (c) 100
  36. 36.Best estimate of 209 + 443? (a) 800 (b) 400 (c) 600
  37. 37.Best estimate of 27 × 79? (a) 24000 (b) 240 (c) 2400
  38. 38.Best estimate of 89 × 62? (a) 54000 (b) 5400 (c) 540
  39. 39.Best estimate of 822 + 780? (a) 1600 (b) 1400 (c) 1800
  40. 40.Best estimate of 32 × 56? (a) 180 (b) 18000 (c) 1800

Answer key

  1. 4500
  2. 1200
  3. 6300
  4. 2400
  5. 900
  6. 3500
  7. 500
  8. 1200
  9. 2700
  10. 1000
  11. 700
  12. 1300
  13. 2000
  14. 600
  15. 3000
  16. 800
  17. 900
  18. 1200
  19. 1200
  20. 1600
  21. 1800
  22. 1200
  23. 500
  24. 900
  25. 600
  26. 1000
  27. 5400
  28. 700
  29. 1000
  30. 600
  31. 1200
  32. 8000
  33. 1100
  34. 800
  35. 1000
  36. 600
  37. 2400
  38. 5400
  39. 1600
  40. 1800

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