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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 188 · 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 12 × 72? (a) 7000 (b) 70 (c) 700
  2. 2.Best estimate of 20 × 73? (a) 14000 (b) 1400 (c) 140
  3. 3.Best estimate of 76 × 34? (a) 240 (b) 2400 (c) 24000
  4. 4.Best estimate of 28 × 37? (a) 120 (b) 12000 (c) 1200
  5. 5.Best estimate of 124 + 681? (a) 1000 (b) 600 (c) 800
  6. 6.Best estimate of 615 + 295? (a) 700 (b) 1100 (c) 900
  7. 7.Best estimate of 503 + 403? (a) 1100 (b) 700 (c) 900
  8. 8.Best estimate of 296 + 233? (a) 500 (b) 700 (c) 300
  9. 9.Best estimate of 94 × 59? (a) 54000 (b) 5400 (c) 540
  10. 10.Best estimate of 570 + 293? (a) 700 (b) 900 (c) 1100
  11. 11.Best estimate of 91 × 42? (a) 360 (b) 3600 (c) 36000
  12. 12.Best estimate of 567 + 165? (a) 1000 (b) 800 (c) 600
  13. 13.Best estimate of 58 × 42? (a) 24000 (b) 240 (c) 2400
  14. 14.Best estimate of 97 × 86? (a) 9000 (b) 900 (c) 90000
  15. 15.Best estimate of 93 × 76? (a) 7200 (b) 72000 (c) 720
  16. 16.Best estimate of 28 × 64? (a) 18000 (b) 180 (c) 1800
  17. 17.Best estimate of 705 + 331? (a) 800 (b) 1200 (c) 1000
  18. 18.Best estimate of 286 + 606? (a) 700 (b) 1100 (c) 900
  19. 19.Best estimate of 87 × 52? (a) 450 (b) 45000 (c) 4500
  20. 20.Best estimate of 12 × 43? (a) 400 (b) 40 (c) 4000
  21. 21.Best estimate of 30 × 87? (a) 270 (b) 27000 (c) 2700
  22. 22.Best estimate of 46 × 49? (a) 250 (b) 2500 (c) 25000
  23. 23.Best estimate of 24 × 47? (a) 1000 (b) 10000 (c) 100
  24. 24.Best estimate of 756 + 572? (a) 1200 (b) 1400 (c) 1600
  25. 25.Best estimate of 479 + 317? (a) 600 (b) 800 (c) 1000
  26. 26.Best estimate of 733 + 426? (a) 1100 (b) 900 (c) 1300
  27. 27.Best estimate of 194 + 455? (a) 700 (b) 900 (c) 500
  28. 28.Best estimate of 833 + 611? (a) 1200 (b) 1600 (c) 1400
  29. 29.Best estimate of 97 × 26? (a) 30000 (b) 300 (c) 3000
  30. 30.Best estimate of 501 + 825? (a) 1500 (b) 1100 (c) 1300
  31. 31.Best estimate of 59 × 14? (a) 60 (b) 6000 (c) 600
  32. 32.Best estimate of 393 + 651? (a) 900 (b) 1300 (c) 1100
  33. 33.Best estimate of 290 + 834? (a) 900 (b) 1100 (c) 1300
  34. 34.Best estimate of 498 + 308? (a) 800 (b) 1000 (c) 600
  35. 35.Best estimate of 80 × 81? (a) 64000 (b) 6400 (c) 640
  36. 36.Best estimate of 849 + 199? (a) 1000 (b) 800 (c) 1200
  37. 37.Best estimate of 47 × 72? (a) 3500 (b) 35000 (c) 350
  38. 38.Best estimate of 49 × 18? (a) 1000 (b) 100 (c) 10000
  39. 39.Best estimate of 41 × 66? (a) 2800 (b) 280 (c) 28000
  40. 40.Best estimate of 753 + 782? (a) 1800 (b) 1400 (c) 1600

Answer key

  1. 700
  2. 1400
  3. 2400
  4. 1200
  5. 800
  6. 900
  7. 900
  8. 500
  9. 5400
  10. 900
  11. 3600
  12. 800
  13. 2400
  14. 9000
  15. 7200
  16. 1800
  17. 1000
  18. 900
  19. 4500
  20. 400
  21. 2700
  22. 2500
  23. 1000
  24. 1400
  25. 800
  26. 1100
  27. 700
  28. 1400
  29. 3000
  30. 1300
  31. 600
  32. 1100
  33. 1100
  34. 800
  35. 6400
  36. 1000
  37. 3500
  38. 1000
  39. 2800
  40. 1600

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