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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 185 · 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 76 × 68? (a) 56000 (b) 560 (c) 5600
  2. 2.Best estimate of 36 × 73? (a) 2800 (b) 28000 (c) 280
  3. 3.Best estimate of 31 × 27? (a) 900 (b) 90 (c) 9000
  4. 4.Best estimate of 214 + 659? (a) 900 (b) 1100 (c) 700
  5. 5.Best estimate of 22 × 61? (a) 120 (b) 1200 (c) 12000
  6. 6.Best estimate of 173 + 859? (a) 900 (b) 1300 (c) 1100
  7. 7.Best estimate of 64 × 97? (a) 600 (b) 60000 (c) 6000
  8. 8.Best estimate of 330 + 498? (a) 800 (b) 1000 (c) 600
  9. 9.Best estimate of 265 + 552? (a) 900 (b) 1100 (c) 700
  10. 10.Best estimate of 79 × 52? (a) 400 (b) 4000 (c) 40000
  11. 11.Best estimate of 713 + 458? (a) 1000 (b) 1400 (c) 1200
  12. 12.Best estimate of 505 + 856? (a) 1600 (b) 1400 (c) 1200
  13. 13.Best estimate of 69 × 64? (a) 4200 (b) 42000 (c) 420
  14. 14.Best estimate of 84 × 89? (a) 720 (b) 7200 (c) 72000
  15. 15.Best estimate of 714 + 627? (a) 1500 (b) 1300 (c) 1100
  16. 16.Best estimate of 62 × 33? (a) 18000 (b) 180 (c) 1800
  17. 17.Best estimate of 200 + 236? (a) 400 (b) 600 (c) 200
  18. 18.Best estimate of 40 × 69? (a) 28000 (b) 280 (c) 2800
  19. 19.Best estimate of 152 + 311? (a) 500 (b) 300 (c) 700
  20. 20.Best estimate of 92 × 66? (a) 630 (b) 63000 (c) 6300
  21. 21.Best estimate of 26 × 92? (a) 270 (b) 2700 (c) 27000
  22. 22.Best estimate of 66 × 66? (a) 4900 (b) 490 (c) 49000
  23. 23.Best estimate of 842 + 430? (a) 1200 (b) 1400 (c) 1000
  24. 24.Best estimate of 74 × 23? (a) 1400 (b) 140 (c) 14000
  25. 25.Best estimate of 16 × 40? (a) 80 (b) 8000 (c) 800
  26. 26.Best estimate of 192 + 335? (a) 500 (b) 700 (c) 300
  27. 27.Best estimate of 516 + 280? (a) 1000 (b) 800 (c) 600
  28. 28.Best estimate of 260 + 443? (a) 900 (b) 500 (c) 700
  29. 29.Best estimate of 39 × 69? (a) 280 (b) 2800 (c) 28000
  30. 30.Best estimate of 62 × 57? (a) 360 (b) 36000 (c) 3600
  31. 31.Best estimate of 235 + 154? (a) 600 (b) 200 (c) 400
  32. 32.Best estimate of 76 × 22? (a) 1600 (b) 16000 (c) 160
  33. 33.Best estimate of 56 × 27? (a) 180 (b) 18000 (c) 1800
  34. 34.Best estimate of 34 × 64? (a) 1800 (b) 18000 (c) 180
  35. 35.Best estimate of 339 + 162? (a) 500 (b) 300 (c) 700
  36. 36.Best estimate of 89 × 24? (a) 180 (b) 1800 (c) 18000
  37. 37.Best estimate of 48 × 96? (a) 500 (b) 5000 (c) 50000
  38. 38.Best estimate of 718 + 790? (a) 1300 (b) 1700 (c) 1500
  39. 39.Best estimate of 596 + 252? (a) 1100 (b) 900 (c) 700
  40. 40.Best estimate of 532 + 636? (a) 900 (b) 1300 (c) 1100

Answer key

  1. 5600
  2. 2800
  3. 900
  4. 900
  5. 1200
  6. 1100
  7. 6000
  8. 800
  9. 900
  10. 4000
  11. 1200
  12. 1400
  13. 4200
  14. 7200
  15. 1300
  16. 1800
  17. 400
  18. 2800
  19. 500
  20. 6300
  21. 2700
  22. 4900
  23. 1200
  24. 1400
  25. 800
  26. 500
  27. 800
  28. 700
  29. 2800
  30. 3600
  31. 400
  32. 1600
  33. 1800
  34. 1800
  35. 500
  36. 1800
  37. 5000
  38. 1500
  39. 900
  40. 1100

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