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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 536 · 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 59 × 48? (a) 30000 (b) 3000 (c) 300
  2. 2.Best estimate of 529 + 454? (a) 800 (b) 1000 (c) 1200
  3. 3.Best estimate of 392 + 319? (a) 700 (b) 900 (c) 500
  4. 4.Best estimate of 456 + 683? (a) 1200 (b) 1000 (c) 1400
  5. 5.Best estimate of 81 × 86? (a) 720 (b) 72000 (c) 7200
  6. 6.Best estimate of 600 + 147? (a) 500 (b) 700 (c) 900
  7. 7.Best estimate of 121 + 752? (a) 700 (b) 900 (c) 1100
  8. 8.Best estimate of 580 + 237? (a) 800 (b) 1000 (c) 600
  9. 9.Best estimate of 403 + 589? (a) 800 (b) 1000 (c) 1200
  10. 10.Best estimate of 53 × 26? (a) 15000 (b) 1500 (c) 150
  11. 11.Best estimate of 703 + 262? (a) 1200 (b) 1000 (c) 800
  12. 12.Best estimate of 22 × 27? (a) 600 (b) 60 (c) 6000
  13. 13.Best estimate of 480 + 613? (a) 900 (b) 1300 (c) 1100
  14. 14.Best estimate of 18 × 71? (a) 1400 (b) 14000 (c) 140
  15. 15.Best estimate of 68 × 93? (a) 63000 (b) 6300 (c) 630
  16. 16.Best estimate of 88 × 68? (a) 6300 (b) 63000 (c) 630
  17. 17.Best estimate of 662 + 358? (a) 900 (b) 1100 (c) 1300
  18. 18.Best estimate of 39 × 66? (a) 28000 (b) 280 (c) 2800
  19. 19.Best estimate of 866 + 315? (a) 1200 (b) 1400 (c) 1000
  20. 20.Best estimate of 26 × 46? (a) 15000 (b) 1500 (c) 150
  21. 21.Best estimate of 90 × 20? (a) 180 (b) 1800 (c) 18000
  22. 22.Best estimate of 878 + 324? (a) 1400 (b) 1000 (c) 1200
  23. 23.Best estimate of 504 + 225? (a) 900 (b) 700 (c) 500
  24. 24.Best estimate of 202 + 715? (a) 1100 (b) 900 (c) 700
  25. 25.Best estimate of 34 × 64? (a) 1800 (b) 18000 (c) 180
  26. 26.Best estimate of 23 × 37? (a) 8000 (b) 800 (c) 80
  27. 27.Best estimate of 26 × 21? (a) 60 (b) 600 (c) 6000
  28. 28.Best estimate of 136 + 197? (a) 100 (b) 500 (c) 300
  29. 29.Best estimate of 63 × 37? (a) 2400 (b) 24000 (c) 240
  30. 30.Best estimate of 170 + 153? (a) 400 (b) 600 (c) 200
  31. 31.Best estimate of 36 × 32? (a) 1200 (b) 12000 (c) 120
  32. 32.Best estimate of 265 + 429? (a) 500 (b) 900 (c) 700
  33. 33.Best estimate of 425 + 609? (a) 1200 (b) 1000 (c) 800
  34. 34.Best estimate of 16 × 34? (a) 60 (b) 600 (c) 6000
  35. 35.Best estimate of 221 + 834? (a) 1000 (b) 800 (c) 1200
  36. 36.Best estimate of 777 + 135? (a) 1100 (b) 900 (c) 700
  37. 37.Best estimate of 86 × 30? (a) 27000 (b) 2700 (c) 270
  38. 38.Best estimate of 672 + 430? (a) 900 (b) 1300 (c) 1100
  39. 39.Best estimate of 315 + 781? (a) 1300 (b) 1100 (c) 900
  40. 40.Best estimate of 79 × 64? (a) 480 (b) 4800 (c) 48000

Answer key

  1. 3000
  2. 1000
  3. 700
  4. 1200
  5. 7200
  6. 700
  7. 900
  8. 800
  9. 1000
  10. 1500
  11. 1000
  12. 600
  13. 1100
  14. 1400
  15. 6300
  16. 6300
  17. 1100
  18. 2800
  19. 1200
  20. 1500
  21. 1800
  22. 1200
  23. 700
  24. 900
  25. 1800
  26. 800
  27. 600
  28. 300
  29. 2400
  30. 400
  31. 1200
  32. 700
  33. 1000
  34. 600
  35. 1000
  36. 900
  37. 2700
  38. 1100
  39. 1100
  40. 4800

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