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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 937 · 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 847 + 830? (a) 1400 (b) 1600 (c) 1800
  2. 2.Best estimate of 71 × 32? (a) 21000 (b) 2100 (c) 210
  3. 3.Best estimate of 84 × 28? (a) 240 (b) 2400 (c) 24000
  4. 4.Best estimate of 26 × 26? (a) 900 (b) 9000 (c) 90
  5. 5.Best estimate of 86 × 21? (a) 180 (b) 1800 (c) 18000
  6. 6.Best estimate of 18 × 68? (a) 1400 (b) 14000 (c) 140
  7. 7.Best estimate of 423 + 666? (a) 1300 (b) 1100 (c) 900
  8. 8.Best estimate of 52 × 58? (a) 300 (b) 3000 (c) 30000
  9. 9.Best estimate of 241 + 164? (a) 200 (b) 600 (c) 400
  10. 10.Best estimate of 879 + 741? (a) 1400 (b) 1600 (c) 1800
  11. 11.Best estimate of 34 × 88? (a) 2700 (b) 27000 (c) 270
  12. 12.Best estimate of 52 × 23? (a) 1000 (b) 10000 (c) 100
  13. 13.Best estimate of 227 + 636? (a) 600 (b) 1000 (c) 800
  14. 14.Best estimate of 154 + 787? (a) 1000 (b) 800 (c) 1200
  15. 15.Best estimate of 43 × 49? (a) 2000 (b) 20000 (c) 200
  16. 16.Best estimate of 36 × 23? (a) 80 (b) 8000 (c) 800
  17. 17.Best estimate of 602 + 692? (a) 1300 (b) 1100 (c) 1500
  18. 18.Best estimate of 97 × 27? (a) 3000 (b) 30000 (c) 300
  19. 19.Best estimate of 33 × 50? (a) 15000 (b) 150 (c) 1500
  20. 20.Best estimate of 84 × 42? (a) 32000 (b) 3200 (c) 320
  21. 21.Best estimate of 337 + 136? (a) 400 (b) 600 (c) 200
  22. 22.Best estimate of 437 + 641? (a) 800 (b) 1200 (c) 1000
  23. 23.Best estimate of 34 × 44? (a) 1200 (b) 12000 (c) 120
  24. 24.Best estimate of 583 + 637? (a) 1200 (b) 1000 (c) 1400
  25. 25.Best estimate of 96 × 81? (a) 8000 (b) 80000 (c) 800
  26. 26.Best estimate of 52 × 87? (a) 4500 (b) 450 (c) 45000
  27. 27.Best estimate of 43 × 14? (a) 40 (b) 400 (c) 4000
  28. 28.Best estimate of 440 + 876? (a) 1100 (b) 1300 (c) 1500
  29. 29.Best estimate of 125 + 479? (a) 600 (b) 400 (c) 800
  30. 30.Best estimate of 673 + 851? (a) 1600 (b) 1400 (c) 1800
  31. 31.Best estimate of 56 × 18? (a) 1200 (b) 120 (c) 12000
  32. 32.Best estimate of 426 + 839? (a) 1400 (b) 1200 (c) 1000
  33. 33.Best estimate of 26 × 17? (a) 60 (b) 600 (c) 6000
  34. 34.Best estimate of 876 + 331? (a) 1000 (b) 1200 (c) 1400
  35. 35.Best estimate of 96 × 63? (a) 6000 (b) 60000 (c) 600
  36. 36.Best estimate of 92 × 36? (a) 3600 (b) 36000 (c) 360
  37. 37.Best estimate of 16 × 89? (a) 1800 (b) 18000 (c) 180
  38. 38.Best estimate of 824 + 273? (a) 900 (b) 1100 (c) 1300
  39. 39.Best estimate of 57 × 44? (a) 2400 (b) 24000 (c) 240
  40. 40.Best estimate of 439 + 554? (a) 1000 (b) 800 (c) 1200

Answer key

  1. 1600
  2. 2100
  3. 2400
  4. 900
  5. 1800
  6. 1400
  7. 1100
  8. 3000
  9. 400
  10. 1600
  11. 2700
  12. 1000
  13. 800
  14. 1000
  15. 2000
  16. 800
  17. 1300
  18. 3000
  19. 1500
  20. 3200
  21. 400
  22. 1000
  23. 1200
  24. 1200
  25. 8000
  26. 4500
  27. 400
  28. 1300
  29. 600
  30. 1600
  31. 1200
  32. 1200
  33. 600
  34. 1200
  35. 6000
  36. 3600
  37. 1800
  38. 1100
  39. 2400
  40. 1000

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