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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 567 · 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 81 × 87? (a) 72000 (b) 720 (c) 7200
  2. 2.Best estimate of 404 + 340? (a) 900 (b) 500 (c) 700
  3. 3.Best estimate of 67 × 24? (a) 14000 (b) 1400 (c) 140
  4. 4.Best estimate of 602 + 716? (a) 1100 (b) 1500 (c) 1300
  5. 5.Best estimate of 545 + 225? (a) 500 (b) 700 (c) 900
  6. 6.Best estimate of 56 × 16? (a) 12000 (b) 1200 (c) 120
  7. 7.Best estimate of 602 + 546? (a) 900 (b) 1300 (c) 1100
  8. 8.Best estimate of 64 × 42? (a) 24000 (b) 240 (c) 2400
  9. 9.Best estimate of 13 × 64? (a) 6000 (b) 600 (c) 60
  10. 10.Best estimate of 577 + 203? (a) 600 (b) 800 (c) 1000
  11. 11.Best estimate of 691 + 309? (a) 1200 (b) 1000 (c) 800
  12. 12.Best estimate of 81 × 51? (a) 400 (b) 40000 (c) 4000
  13. 13.Best estimate of 551 + 295? (a) 900 (b) 700 (c) 1100
  14. 14.Best estimate of 36 × 94? (a) 360 (b) 3600 (c) 36000
  15. 15.Best estimate of 326 + 771? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 57 × 63? (a) 3600 (b) 360 (c) 36000
  17. 17.Best estimate of 28 × 68? (a) 2100 (b) 21000 (c) 210
  18. 18.Best estimate of 758 + 805? (a) 1800 (b) 1600 (c) 1400
  19. 19.Best estimate of 416 + 587? (a) 800 (b) 1000 (c) 1200
  20. 20.Best estimate of 67 × 52? (a) 350 (b) 35000 (c) 3500
  21. 21.Best estimate of 649 + 160? (a) 1000 (b) 800 (c) 600
  22. 22.Best estimate of 788 + 773? (a) 1400 (b) 1600 (c) 1800
  23. 23.Best estimate of 721 + 544? (a) 1000 (b) 1400 (c) 1200
  24. 24.Best estimate of 752 + 485? (a) 1500 (b) 1300 (c) 1100
  25. 25.Best estimate of 74 × 80? (a) 560 (b) 56000 (c) 5600
  26. 26.Best estimate of 57 × 40? (a) 24000 (b) 2400 (c) 240
  27. 27.Best estimate of 514 + 427? (a) 700 (b) 900 (c) 1100
  28. 28.Best estimate of 251 + 248? (a) 300 (b) 500 (c) 700
  29. 29.Best estimate of 794 + 669? (a) 1300 (b) 1700 (c) 1500
  30. 30.Best estimate of 748 + 533? (a) 1200 (b) 1400 (c) 1000
  31. 31.Best estimate of 234 + 783? (a) 1000 (b) 1200 (c) 800
  32. 32.Best estimate of 495 + 455? (a) 1200 (b) 1000 (c) 800
  33. 33.Best estimate of 364 + 657? (a) 1100 (b) 1300 (c) 900
  34. 34.Best estimate of 78 × 16? (a) 1600 (b) 160 (c) 16000
  35. 35.Best estimate of 288 + 453? (a) 800 (b) 1000 (c) 600
  36. 36.Best estimate of 427 + 289? (a) 900 (b) 500 (c) 700
  37. 37.Best estimate of 694 + 405? (a) 900 (b) 1100 (c) 1300
  38. 38.Best estimate of 22 × 27? (a) 600 (b) 60 (c) 6000
  39. 39.Best estimate of 123 + 304? (a) 600 (b) 200 (c) 400
  40. 40.Best estimate of 13 × 61? (a) 60 (b) 600 (c) 6000

Answer key

  1. 7200
  2. 700
  3. 1400
  4. 1300
  5. 700
  6. 1200
  7. 1100
  8. 2400
  9. 600
  10. 800
  11. 1000
  12. 4000
  13. 900
  14. 3600
  15. 1100
  16. 3600
  17. 2100
  18. 1600
  19. 1000
  20. 3500
  21. 800
  22. 1600
  23. 1200
  24. 1300
  25. 5600
  26. 2400
  27. 900
  28. 500
  29. 1500
  30. 1200
  31. 1000
  32. 1000
  33. 1100
  34. 1600
  35. 800
  36. 700
  37. 1100
  38. 600
  39. 400
  40. 600

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