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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 197 · 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 82 × 74? (a) 56000 (b) 560 (c) 5600
  2. 2.Best estimate of 26 × 46? (a) 15000 (b) 150 (c) 1500
  3. 3.Best estimate of 570 + 695? (a) 1100 (b) 1500 (c) 1300
  4. 4.Best estimate of 539 + 249? (a) 500 (b) 900 (c) 700
  5. 5.Best estimate of 86 × 96? (a) 90000 (b) 9000 (c) 900
  6. 6.Best estimate of 351 + 639? (a) 1000 (b) 1200 (c) 800
  7. 7.Best estimate of 83 × 69? (a) 560 (b) 56000 (c) 5600
  8. 8.Best estimate of 878 + 677? (a) 1800 (b) 1400 (c) 1600
  9. 9.Best estimate of 675 + 682? (a) 1200 (b) 1400 (c) 1600
  10. 10.Best estimate of 90 × 29? (a) 2700 (b) 270 (c) 27000
  11. 11.Best estimate of 59 × 39? (a) 2400 (b) 240 (c) 24000
  12. 12.Best estimate of 182 + 408? (a) 600 (b) 800 (c) 400
  13. 13.Best estimate of 649 + 243? (a) 1000 (b) 800 (c) 600
  14. 14.Best estimate of 74 × 58? (a) 420 (b) 4200 (c) 42000
  15. 15.Best estimate of 597 + 371? (a) 1000 (b) 800 (c) 1200
  16. 16.Best estimate of 33 × 93? (a) 2700 (b) 27000 (c) 270
  17. 17.Best estimate of 93 × 87? (a) 810 (b) 8100 (c) 81000
  18. 18.Best estimate of 506 + 773? (a) 1500 (b) 1300 (c) 1100
  19. 19.Best estimate of 69 × 61? (a) 42000 (b) 420 (c) 4200
  20. 20.Best estimate of 832 + 588? (a) 1600 (b) 1200 (c) 1400
  21. 21.Best estimate of 523 + 474? (a) 1000 (b) 1200 (c) 800
  22. 22.Best estimate of 77 × 16? (a) 160 (b) 16000 (c) 1600
  23. 23.Best estimate of 70 × 69? (a) 49000 (b) 4900 (c) 490
  24. 24.Best estimate of 511 + 334? (a) 600 (b) 800 (c) 1000
  25. 25.Best estimate of 86 × 92? (a) 81000 (b) 810 (c) 8100
  26. 26.Best estimate of 66 × 98? (a) 700 (b) 70000 (c) 7000
  27. 27.Best estimate of 46 × 48? (a) 250 (b) 2500 (c) 25000
  28. 28.Best estimate of 61 × 22? (a) 12000 (b) 1200 (c) 120
  29. 29.Best estimate of 48 × 32? (a) 1500 (b) 150 (c) 15000
  30. 30.Best estimate of 68 × 73? (a) 4900 (b) 49000 (c) 490
  31. 31.Best estimate of 721 + 288? (a) 1200 (b) 1000 (c) 800
  32. 32.Best estimate of 93 × 37? (a) 36000 (b) 3600 (c) 360
  33. 33.Best estimate of 218 + 288? (a) 700 (b) 500 (c) 300
  34. 34.Best estimate of 60 × 23? (a) 120 (b) 1200 (c) 12000
  35. 35.Best estimate of 71 × 92? (a) 6300 (b) 63000 (c) 630
  36. 36.Best estimate of 132 + 845? (a) 900 (b) 1100 (c) 700
  37. 37.Best estimate of 66 × 29? (a) 210 (b) 21000 (c) 2100
  38. 38.Best estimate of 280 + 700? (a) 1200 (b) 1000 (c) 800
  39. 39.Best estimate of 91 × 13? (a) 9000 (b) 90 (c) 900
  40. 40.Best estimate of 795 + 811? (a) 1600 (b) 1800 (c) 1400

Answer key

  1. 5600
  2. 1500
  3. 1300
  4. 700
  5. 9000
  6. 1000
  7. 5600
  8. 1600
  9. 1400
  10. 2700
  11. 2400
  12. 600
  13. 800
  14. 4200
  15. 1000
  16. 2700
  17. 8100
  18. 1300
  19. 4200
  20. 1400
  21. 1000
  22. 1600
  23. 4900
  24. 800
  25. 8100
  26. 7000
  27. 2500
  28. 1200
  29. 1500
  30. 4900
  31. 1000
  32. 3600
  33. 500
  34. 1200
  35. 6300
  36. 900
  37. 2100
  38. 1000
  39. 900
  40. 1600

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