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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 178 · 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 376 + 763? (a) 1400 (b) 1200 (c) 1000
  2. 2.Best estimate of 851 + 415? (a) 1500 (b) 1300 (c) 1100
  3. 3.Best estimate of 837 + 577? (a) 1400 (b) 1200 (c) 1600
  4. 4.Best estimate of 63 × 13? (a) 600 (b) 60 (c) 6000
  5. 5.Best estimate of 717 + 736? (a) 1400 (b) 1200 (c) 1600
  6. 6.Best estimate of 96 × 66? (a) 7000 (b) 70000 (c) 700
  7. 7.Best estimate of 671 + 657? (a) 1200 (b) 1600 (c) 1400
  8. 8.Best estimate of 697 + 468? (a) 1000 (b) 1200 (c) 1400
  9. 9.Best estimate of 454 + 272? (a) 1000 (b) 800 (c) 600
  10. 10.Best estimate of 847 + 134? (a) 900 (b) 1100 (c) 700
  11. 11.Best estimate of 216 + 181? (a) 200 (b) 400 (c) 600
  12. 12.Best estimate of 510 + 536? (a) 800 (b) 1000 (c) 1200
  13. 13.Best estimate of 79 × 20? (a) 160 (b) 16000 (c) 1600
  14. 14.Best estimate of 36 × 36? (a) 16000 (b) 160 (c) 1600
  15. 15.Best estimate of 80 × 31? (a) 24000 (b) 2400 (c) 240
  16. 16.Best estimate of 86 × 97? (a) 9000 (b) 90000 (c) 900
  17. 17.Best estimate of 96 × 12? (a) 100 (b) 1000 (c) 10000
  18. 18.Best estimate of 670 + 755? (a) 1700 (b) 1500 (c) 1300
  19. 19.Best estimate of 188 + 724? (a) 1100 (b) 900 (c) 700
  20. 20.Best estimate of 28 × 18? (a) 600 (b) 60 (c) 6000
  21. 21.Best estimate of 211 + 306? (a) 300 (b) 700 (c) 500
  22. 22.Best estimate of 674 + 478? (a) 1400 (b) 1200 (c) 1000
  23. 23.Best estimate of 83 × 33? (a) 2400 (b) 24000 (c) 240
  24. 24.Best estimate of 29 × 12? (a) 3000 (b) 30 (c) 300
  25. 25.Best estimate of 48 × 26? (a) 150 (b) 1500 (c) 15000
  26. 26.Best estimate of 36 × 47? (a) 200 (b) 20000 (c) 2000
  27. 27.Best estimate of 66 × 42? (a) 28000 (b) 280 (c) 2800
  28. 28.Best estimate of 151 + 517? (a) 900 (b) 700 (c) 500
  29. 29.Best estimate of 679 + 332? (a) 800 (b) 1200 (c) 1000
  30. 30.Best estimate of 12 × 33? (a) 300 (b) 3000 (c) 30
  31. 31.Best estimate of 269 + 172? (a) 500 (b) 300 (c) 700
  32. 32.Best estimate of 220 + 661? (a) 700 (b) 1100 (c) 900
  33. 33.Best estimate of 92 × 36? (a) 36000 (b) 3600 (c) 360
  34. 34.Best estimate of 341 + 198? (a) 300 (b) 700 (c) 500
  35. 35.Best estimate of 657 + 136? (a) 600 (b) 1000 (c) 800
  36. 36.Best estimate of 408 + 692? (a) 1300 (b) 900 (c) 1100
  37. 37.Best estimate of 76 × 27? (a) 24000 (b) 240 (c) 2400
  38. 38.Best estimate of 844 + 389? (a) 1400 (b) 1200 (c) 1000
  39. 39.Best estimate of 87 × 70? (a) 63000 (b) 630 (c) 6300
  40. 40.Best estimate of 207 + 424? (a) 400 (b) 600 (c) 800

Answer key

  1. 1200
  2. 1300
  3. 1400
  4. 600
  5. 1400
  6. 7000
  7. 1400
  8. 1200
  9. 800
  10. 900
  11. 400
  12. 1000
  13. 1600
  14. 1600
  15. 2400
  16. 9000
  17. 1000
  18. 1500
  19. 900
  20. 600
  21. 500
  22. 1200
  23. 2400
  24. 300
  25. 1500
  26. 2000
  27. 2800
  28. 700
  29. 1000
  30. 300
  31. 500
  32. 900
  33. 3600
  34. 500
  35. 800
  36. 1100
  37. 2400
  38. 1200
  39. 6300
  40. 600

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