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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 625 · 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 44 × 66? (a) 280 (b) 28000 (c) 2800
  2. 2.Best estimate of 879 + 135? (a) 1200 (b) 1000 (c) 800
  3. 3.Best estimate of 86 × 17? (a) 1800 (b) 180 (c) 18000
  4. 4.Best estimate of 796 + 880? (a) 1500 (b) 1700 (c) 1900
  5. 5.Best estimate of 36 × 40? (a) 1600 (b) 160 (c) 16000
  6. 6.Best estimate of 600 + 725? (a) 1300 (b) 1500 (c) 1100
  7. 7.Best estimate of 760 + 615? (a) 1600 (b) 1200 (c) 1400
  8. 8.Best estimate of 861 + 626? (a) 1700 (b) 1500 (c) 1300
  9. 9.Best estimate of 77 × 53? (a) 40000 (b) 4000 (c) 400
  10. 10.Best estimate of 12 × 38? (a) 400 (b) 4000 (c) 40
  11. 11.Best estimate of 40 × 39? (a) 160 (b) 16000 (c) 1600
  12. 12.Best estimate of 577 + 766? (a) 1200 (b) 1400 (c) 1600
  13. 13.Best estimate of 67 × 31? (a) 21000 (b) 210 (c) 2100
  14. 14.Best estimate of 286 + 167? (a) 700 (b) 500 (c) 300
  15. 15.Best estimate of 719 + 241? (a) 900 (b) 1100 (c) 700
  16. 16.Best estimate of 76 × 62? (a) 480 (b) 48000 (c) 4800
  17. 17.Best estimate of 20 × 67? (a) 14000 (b) 1400 (c) 140
  18. 18.Best estimate of 164 + 832? (a) 1200 (b) 1000 (c) 800
  19. 19.Best estimate of 131 + 340? (a) 400 (b) 200 (c) 600
  20. 20.Best estimate of 51 × 69? (a) 35000 (b) 3500 (c) 350
  21. 21.Best estimate of 830 + 862? (a) 1700 (b) 1900 (c) 1500
  22. 22.Best estimate of 233 + 806? (a) 1000 (b) 1200 (c) 800
  23. 23.Best estimate of 43 × 71? (a) 2800 (b) 280 (c) 28000
  24. 24.Best estimate of 707 + 477? (a) 1200 (b) 1400 (c) 1000
  25. 25.Best estimate of 60 × 13? (a) 6000 (b) 60 (c) 600
  26. 26.Best estimate of 53 × 78? (a) 400 (b) 4000 (c) 40000
  27. 27.Best estimate of 751 + 617? (a) 1200 (b) 1400 (c) 1600
  28. 28.Best estimate of 16 × 80? (a) 160 (b) 1600 (c) 16000
  29. 29.Best estimate of 133 + 173? (a) 300 (b) 500 (c) 100
  30. 30.Best estimate of 575 + 811? (a) 1400 (b) 1200 (c) 1600
  31. 31.Best estimate of 335 + 234? (a) 700 (b) 300 (c) 500
  32. 32.Best estimate of 27 × 60? (a) 180 (b) 18000 (c) 1800
  33. 33.Best estimate of 43 × 60? (a) 2400 (b) 240 (c) 24000
  34. 34.Best estimate of 82 × 90? (a) 720 (b) 72000 (c) 7200
  35. 35.Best estimate of 24 × 61? (a) 1200 (b) 12000 (c) 120
  36. 36.Best estimate of 71 × 19? (a) 14000 (b) 1400 (c) 140
  37. 37.Best estimate of 524 + 502? (a) 800 (b) 1000 (c) 1200
  38. 38.Best estimate of 24 × 42? (a) 8000 (b) 80 (c) 800
  39. 39.Best estimate of 415 + 805? (a) 1400 (b) 1200 (c) 1000
  40. 40.Best estimate of 761 + 497? (a) 1100 (b) 1500 (c) 1300

Answer key

  1. 2800
  2. 1000
  3. 1800
  4. 1700
  5. 1600
  6. 1300
  7. 1400
  8. 1500
  9. 4000
  10. 400
  11. 1600
  12. 1400
  13. 2100
  14. 500
  15. 900
  16. 4800
  17. 1400
  18. 1000
  19. 400
  20. 3500
  21. 1700
  22. 1000
  23. 2800
  24. 1200
  25. 600
  26. 4000
  27. 1400
  28. 1600
  29. 300
  30. 1400
  31. 500
  32. 1800
  33. 2400
  34. 7200
  35. 1200
  36. 1400
  37. 1000
  38. 800
  39. 1200
  40. 1300

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