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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 958 · 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 206 + 375? (a) 400 (b) 800 (c) 600
  2. 2.Best estimate of 482 + 281? (a) 1000 (b) 800 (c) 600
  3. 3.Best estimate of 626 + 425? (a) 1000 (b) 800 (c) 1200
  4. 4.Best estimate of 87 × 13? (a) 9000 (b) 900 (c) 90
  5. 5.Best estimate of 126 + 378? (a) 300 (b) 700 (c) 500
  6. 6.Best estimate of 23 × 17? (a) 4000 (b) 40 (c) 400
  7. 7.Best estimate of 66 × 18? (a) 1400 (b) 140 (c) 14000
  8. 8.Best estimate of 56 × 97? (a) 6000 (b) 600 (c) 60000
  9. 9.Best estimate of 533 + 424? (a) 1100 (b) 700 (c) 900
  10. 10.Best estimate of 857 + 714? (a) 1600 (b) 1400 (c) 1800
  11. 11.Best estimate of 864 + 459? (a) 1600 (b) 1200 (c) 1400
  12. 12.Best estimate of 31 × 37? (a) 12000 (b) 1200 (c) 120
  13. 13.Best estimate of 14 × 84? (a) 800 (b) 8000 (c) 80
  14. 14.Best estimate of 684 + 862? (a) 1800 (b) 1600 (c) 1400
  15. 15.Best estimate of 61 × 36? (a) 240 (b) 24000 (c) 2400
  16. 16.Best estimate of 237 + 308? (a) 700 (b) 500 (c) 300
  17. 17.Best estimate of 246 + 770? (a) 800 (b) 1200 (c) 1000
  18. 18.Best estimate of 216 + 469? (a) 700 (b) 500 (c) 900
  19. 19.Best estimate of 70 × 36? (a) 280 (b) 2800 (c) 28000
  20. 20.Best estimate of 60 × 18? (a) 1200 (b) 12000 (c) 120
  21. 21.Best estimate of 54 × 20? (a) 1000 (b) 10000 (c) 100
  22. 22.Best estimate of 58 × 47? (a) 300 (b) 3000 (c) 30000
  23. 23.Best estimate of 56 × 31? (a) 1800 (b) 18000 (c) 180
  24. 24.Best estimate of 156 + 760? (a) 800 (b) 1000 (c) 1200
  25. 25.Best estimate of 14 × 17? (a) 200 (b) 20 (c) 2000
  26. 26.Best estimate of 23 × 53? (a) 100 (b) 1000 (c) 10000
  27. 27.Best estimate of 627 + 239? (a) 1000 (b) 800 (c) 600
  28. 28.Best estimate of 90 × 74? (a) 63000 (b) 630 (c) 6300
  29. 29.Best estimate of 28 × 24? (a) 60 (b) 6000 (c) 600
  30. 30.Best estimate of 17 × 17? (a) 400 (b) 4000 (c) 40
  31. 31.Best estimate of 278 + 300? (a) 400 (b) 800 (c) 600
  32. 32.Best estimate of 509 + 635? (a) 1100 (b) 900 (c) 1300
  33. 33.Best estimate of 214 + 183? (a) 400 (b) 200 (c) 600
  34. 34.Best estimate of 14 × 28? (a) 3000 (b) 30 (c) 300
  35. 35.Best estimate of 511 + 729? (a) 1200 (b) 1000 (c) 1400
  36. 36.Best estimate of 83 × 12? (a) 8000 (b) 80 (c) 800
  37. 37.Best estimate of 46 × 23? (a) 10000 (b) 100 (c) 1000
  38. 38.Best estimate of 385 + 645? (a) 1200 (b) 800 (c) 1000
  39. 39.Best estimate of 846 + 855? (a) 1700 (b) 1500 (c) 1900
  40. 40.Best estimate of 512 + 487? (a) 1000 (b) 800 (c) 1200

Answer key

  1. 600
  2. 800
  3. 1000
  4. 900
  5. 500
  6. 400
  7. 1400
  8. 6000
  9. 900
  10. 1600
  11. 1400
  12. 1200
  13. 800
  14. 1600
  15. 2400
  16. 500
  17. 1000
  18. 700
  19. 2800
  20. 1200
  21. 1000
  22. 3000
  23. 1800
  24. 1000
  25. 200
  26. 1000
  27. 800
  28. 6300
  29. 600
  30. 400
  31. 600
  32. 1100
  33. 400
  34. 300
  35. 1200
  36. 800
  37. 1000
  38. 1000
  39. 1700
  40. 1000

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