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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 114 · 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 24 × 64? (a) 1200 (b) 120 (c) 12000
  2. 2.Best estimate of 301 + 631? (a) 900 (b) 700 (c) 1100
  3. 3.Best estimate of 60 × 91? (a) 5400 (b) 54000 (c) 540
  4. 4.Best estimate of 637 + 403? (a) 1000 (b) 1200 (c) 800
  5. 5.Best estimate of 30 × 39? (a) 12000 (b) 1200 (c) 120
  6. 6.Best estimate of 315 + 365? (a) 700 (b) 500 (c) 900
  7. 7.Best estimate of 357 + 781? (a) 1000 (b) 1400 (c) 1200
  8. 8.Best estimate of 33 × 39? (a) 1200 (b) 120 (c) 12000
  9. 9.Best estimate of 572 + 838? (a) 1600 (b) 1400 (c) 1200
  10. 10.Best estimate of 26 × 31? (a) 900 (b) 90 (c) 9000
  11. 11.Best estimate of 199 + 269? (a) 300 (b) 500 (c) 700
  12. 12.Best estimate of 46 × 33? (a) 15000 (b) 1500 (c) 150
  13. 13.Best estimate of 291 + 271? (a) 400 (b) 600 (c) 800
  14. 14.Best estimate of 229 + 231? (a) 400 (b) 600 (c) 200
  15. 15.Best estimate of 690 + 698? (a) 1400 (b) 1200 (c) 1600
  16. 16.Best estimate of 587 + 295? (a) 700 (b) 900 (c) 1100
  17. 17.Best estimate of 86 × 32? (a) 27000 (b) 270 (c) 2700
  18. 18.Best estimate of 502 + 767? (a) 1300 (b) 1500 (c) 1100
  19. 19.Best estimate of 362 + 207? (a) 600 (b) 400 (c) 800
  20. 20.Best estimate of 31 × 76? (a) 2400 (b) 240 (c) 24000
  21. 21.Best estimate of 290 + 725? (a) 800 (b) 1200 (c) 1000
  22. 22.Best estimate of 86 × 63? (a) 5400 (b) 54000 (c) 540
  23. 23.Best estimate of 606 + 157? (a) 800 (b) 600 (c) 1000
  24. 24.Best estimate of 29 × 83? (a) 240 (b) 24000 (c) 2400
  25. 25.Best estimate of 19 × 78? (a) 160 (b) 16000 (c) 1600
  26. 26.Best estimate of 90 × 91? (a) 8100 (b) 81000 (c) 810
  27. 27.Best estimate of 631 + 294? (a) 900 (b) 1100 (c) 700
  28. 28.Best estimate of 81 × 72? (a) 560 (b) 5600 (c) 56000
  29. 29.Best estimate of 664 + 751? (a) 1300 (b) 1700 (c) 1500
  30. 30.Best estimate of 19 × 91? (a) 180 (b) 18000 (c) 1800
  31. 31.Best estimate of 665 + 323? (a) 1200 (b) 1000 (c) 800
  32. 32.Best estimate of 715 + 493? (a) 1000 (b) 1200 (c) 1400
  33. 33.Best estimate of 92 × 21? (a) 18000 (b) 1800 (c) 180
  34. 34.Best estimate of 520 + 187? (a) 900 (b) 500 (c) 700
  35. 35.Best estimate of 86 × 51? (a) 45000 (b) 4500 (c) 450
  36. 36.Best estimate of 518 + 279? (a) 600 (b) 1000 (c) 800
  37. 37.Best estimate of 405 + 696? (a) 1100 (b) 1300 (c) 900
  38. 38.Best estimate of 86 × 33? (a) 27000 (b) 2700 (c) 270
  39. 39.Best estimate of 37 × 31? (a) 1200 (b) 12000 (c) 120
  40. 40.Best estimate of 36 × 91? (a) 3600 (b) 360 (c) 36000

Answer key

  1. 1200
  2. 900
  3. 5400
  4. 1000
  5. 1200
  6. 700
  7. 1200
  8. 1200
  9. 1400
  10. 900
  11. 500
  12. 1500
  13. 600
  14. 400
  15. 1400
  16. 900
  17. 2700
  18. 1300
  19. 600
  20. 2400
  21. 1000
  22. 5400
  23. 800
  24. 2400
  25. 1600
  26. 8100
  27. 900
  28. 5600
  29. 1500
  30. 1800
  31. 1000
  32. 1200
  33. 1800
  34. 700
  35. 4500
  36. 800
  37. 1100
  38. 2700
  39. 1200
  40. 3600

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