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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 599 · 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 32 × 28? (a) 90 (b) 900 (c) 9000
  2. 2.Best estimate of 368 + 218? (a) 800 (b) 600 (c) 400
  3. 3.Best estimate of 758 + 264? (a) 900 (b) 1100 (c) 1300
  4. 4.Best estimate of 27 × 81? (a) 2400 (b) 24000 (c) 240
  5. 5.Best estimate of 359 + 168? (a) 600 (b) 800 (c) 400
  6. 6.Best estimate of 299 + 695? (a) 1000 (b) 1200 (c) 800
  7. 7.Best estimate of 83 × 47? (a) 40000 (b) 400 (c) 4000
  8. 8.Best estimate of 822 + 694? (a) 1500 (b) 1700 (c) 1300
  9. 9.Best estimate of 16 × 86? (a) 18000 (b) 180 (c) 1800
  10. 10.Best estimate of 70 × 84? (a) 56000 (b) 560 (c) 5600
  11. 11.Best estimate of 28 × 73? (a) 2100 (b) 210 (c) 21000
  12. 12.Best estimate of 511 + 692? (a) 1200 (b) 1400 (c) 1000
  13. 13.Best estimate of 370 + 634? (a) 1200 (b) 1000 (c) 800
  14. 14.Best estimate of 71 × 93? (a) 63000 (b) 6300 (c) 630
  15. 15.Best estimate of 86 × 76? (a) 7200 (b) 720 (c) 72000
  16. 16.Best estimate of 495 + 318? (a) 1000 (b) 800 (c) 600
  17. 17.Best estimate of 372 + 686? (a) 900 (b) 1100 (c) 1300
  18. 18.Best estimate of 741 + 222? (a) 700 (b) 900 (c) 1100
  19. 19.Best estimate of 790 + 661? (a) 1700 (b) 1500 (c) 1300
  20. 20.Best estimate of 607 + 817? (a) 1400 (b) 1200 (c) 1600
  21. 21.Best estimate of 813 + 125? (a) 700 (b) 1100 (c) 900
  22. 22.Best estimate of 736 + 856? (a) 1600 (b) 1800 (c) 1400
  23. 23.Best estimate of 90 × 72? (a) 6300 (b) 63000 (c) 630
  24. 24.Best estimate of 91 × 96? (a) 9000 (b) 90000 (c) 900
  25. 25.Best estimate of 652 + 715? (a) 1200 (b) 1400 (c) 1600
  26. 26.Best estimate of 72 × 77? (a) 56000 (b) 560 (c) 5600
  27. 27.Best estimate of 86 × 54? (a) 45000 (b) 450 (c) 4500
  28. 28.Best estimate of 68 × 56? (a) 4200 (b) 42000 (c) 420
  29. 29.Best estimate of 34 × 61? (a) 18000 (b) 1800 (c) 180
  30. 30.Best estimate of 439 + 613? (a) 1000 (b) 1200 (c) 800
  31. 31.Best estimate of 637 + 618? (a) 1000 (b) 1200 (c) 1400
  32. 32.Best estimate of 89 × 91? (a) 8100 (b) 81000 (c) 810
  33. 33.Best estimate of 52 × 91? (a) 4500 (b) 450 (c) 45000
  34. 34.Best estimate of 374 + 860? (a) 1300 (b) 1100 (c) 1500
  35. 35.Best estimate of 366 + 273? (a) 700 (b) 900 (c) 500
  36. 36.Best estimate of 39 × 36? (a) 1600 (b) 160 (c) 16000
  37. 37.Best estimate of 14 × 30? (a) 3000 (b) 300 (c) 30
  38. 38.Best estimate of 22 × 60? (a) 120 (b) 12000 (c) 1200
  39. 39.Best estimate of 739 + 253? (a) 1000 (b) 1200 (c) 800
  40. 40.Best estimate of 22 × 46? (a) 10000 (b) 100 (c) 1000

Answer key

  1. 900
  2. 600
  3. 1100
  4. 2400
  5. 600
  6. 1000
  7. 4000
  8. 1500
  9. 1800
  10. 5600
  11. 2100
  12. 1200
  13. 1000
  14. 6300
  15. 7200
  16. 800
  17. 1100
  18. 900
  19. 1500
  20. 1400
  21. 900
  22. 1600
  23. 6300
  24. 9000
  25. 1400
  26. 5600
  27. 4500
  28. 4200
  29. 1800
  30. 1000
  31. 1200
  32. 8100
  33. 4500
  34. 1300
  35. 700
  36. 1600
  37. 300
  38. 1200
  39. 1000
  40. 1000

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