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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 981 · 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 774 + 652? (a) 1500 (b) 1300 (c) 1700
  2. 2.Best estimate of 58 × 14? (a) 600 (b) 60 (c) 6000
  3. 3.Best estimate of 355 + 222? (a) 600 (b) 400 (c) 800
  4. 4.Best estimate of 412 + 563? (a) 800 (b) 1000 (c) 1200
  5. 5.Best estimate of 92 × 46? (a) 450 (b) 4500 (c) 45000
  6. 6.Best estimate of 52 × 43? (a) 2000 (b) 20000 (c) 200
  7. 7.Best estimate of 340 + 683? (a) 1200 (b) 1000 (c) 800
  8. 8.Best estimate of 64 × 52? (a) 30000 (b) 300 (c) 3000
  9. 9.Best estimate of 27 × 21? (a) 60 (b) 6000 (c) 600
  10. 10.Best estimate of 636 + 129? (a) 700 (b) 500 (c) 900
  11. 11.Best estimate of 90 × 24? (a) 180 (b) 18000 (c) 1800
  12. 12.Best estimate of 66 × 52? (a) 350 (b) 35000 (c) 3500
  13. 13.Best estimate of 90 × 26? (a) 270 (b) 27000 (c) 2700
  14. 14.Best estimate of 93 × 74? (a) 6300 (b) 630 (c) 63000
  15. 15.Best estimate of 124 + 663? (a) 600 (b) 1000 (c) 800
  16. 16.Best estimate of 464 + 645? (a) 1100 (b) 900 (c) 1300
  17. 17.Best estimate of 28 × 98? (a) 30000 (b) 300 (c) 3000
  18. 18.Best estimate of 788 + 710? (a) 1700 (b) 1500 (c) 1300
  19. 19.Best estimate of 275 + 640? (a) 900 (b) 1100 (c) 700
  20. 20.Best estimate of 34 × 96? (a) 300 (b) 30000 (c) 3000
  21. 21.Best estimate of 46 × 39? (a) 200 (b) 2000 (c) 20000
  22. 22.Best estimate of 37 × 49? (a) 20000 (b) 2000 (c) 200
  23. 23.Best estimate of 86 × 32? (a) 2700 (b) 27000 (c) 270
  24. 24.Best estimate of 468 + 657? (a) 1000 (b) 1400 (c) 1200
  25. 25.Best estimate of 68 × 36? (a) 2800 (b) 280 (c) 28000
  26. 26.Best estimate of 407 + 207? (a) 400 (b) 800 (c) 600
  27. 27.Best estimate of 89 × 13? (a) 90 (b) 9000 (c) 900
  28. 28.Best estimate of 360 + 611? (a) 800 (b) 1000 (c) 1200
  29. 29.Best estimate of 26 × 64? (a) 180 (b) 18000 (c) 1800
  30. 30.Best estimate of 64 × 77? (a) 480 (b) 48000 (c) 4800
  31. 31.Best estimate of 26 × 66? (a) 2100 (b) 210 (c) 21000
  32. 32.Best estimate of 148 + 597? (a) 500 (b) 900 (c) 700
  33. 33.Best estimate of 36 × 84? (a) 32000 (b) 320 (c) 3200
  34. 34.Best estimate of 63 × 41? (a) 2400 (b) 24000 (c) 240
  35. 35.Best estimate of 14 × 93? (a) 900 (b) 90 (c) 9000
  36. 36.Best estimate of 18 × 21? (a) 4000 (b) 400 (c) 40
  37. 37.Best estimate of 40 × 14? (a) 400 (b) 4000 (c) 40
  38. 38.Best estimate of 19 × 47? (a) 1000 (b) 10000 (c) 100
  39. 39.Best estimate of 878 + 674? (a) 1800 (b) 1600 (c) 1400
  40. 40.Best estimate of 687 + 293? (a) 800 (b) 1200 (c) 1000

Answer key

  1. 1500
  2. 600
  3. 600
  4. 1000
  5. 4500
  6. 2000
  7. 1000
  8. 3000
  9. 600
  10. 700
  11. 1800
  12. 3500
  13. 2700
  14. 6300
  15. 800
  16. 1100
  17. 3000
  18. 1500
  19. 900
  20. 3000
  21. 2000
  22. 2000
  23. 2700
  24. 1200
  25. 2800
  26. 600
  27. 900
  28. 1000
  29. 1800
  30. 4800
  31. 2100
  32. 700
  33. 3200
  34. 2400
  35. 900
  36. 400
  37. 400
  38. 1000
  39. 1600
  40. 1000

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