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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 340 · 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 12 × 86? (a) 90 (b) 9000 (c) 900
  2. 2.Best estimate of 444 + 832? (a) 1000 (b) 1400 (c) 1200
  3. 3.Best estimate of 304 + 481? (a) 1000 (b) 800 (c) 600
  4. 4.Best estimate of 728 + 199? (a) 900 (b) 1100 (c) 700
  5. 5.Best estimate of 664 + 720? (a) 1600 (b) 1400 (c) 1200
  6. 6.Best estimate of 824 + 495? (a) 1500 (b) 1300 (c) 1100
  7. 7.Best estimate of 93 × 16? (a) 1800 (b) 180 (c) 18000
  8. 8.Best estimate of 135 + 847? (a) 900 (b) 1100 (c) 700
  9. 9.Best estimate of 428 + 249? (a) 800 (b) 400 (c) 600
  10. 10.Best estimate of 66 × 73? (a) 49000 (b) 4900 (c) 490
  11. 11.Best estimate of 341 + 878? (a) 1400 (b) 1000 (c) 1200
  12. 12.Best estimate of 123 + 707? (a) 1000 (b) 600 (c) 800
  13. 13.Best estimate of 33 × 97? (a) 300 (b) 3000 (c) 30000
  14. 14.Best estimate of 680 + 816? (a) 1500 (b) 1300 (c) 1700
  15. 15.Best estimate of 268 + 560? (a) 900 (b) 1100 (c) 700
  16. 16.Best estimate of 234 + 599? (a) 600 (b) 1000 (c) 800
  17. 17.Best estimate of 90 × 20? (a) 18000 (b) 1800 (c) 180
  18. 18.Best estimate of 759 + 709? (a) 1300 (b) 1700 (c) 1500
  19. 19.Best estimate of 86 × 92? (a) 81000 (b) 810 (c) 8100
  20. 20.Best estimate of 63 × 52? (a) 300 (b) 3000 (c) 30000
  21. 21.Best estimate of 607 + 607? (a) 1200 (b) 1400 (c) 1000
  22. 22.Best estimate of 852 + 528? (a) 1200 (b) 1600 (c) 1400
  23. 23.Best estimate of 37 × 60? (a) 2400 (b) 24000 (c) 240
  24. 24.Best estimate of 439 + 293? (a) 900 (b) 500 (c) 700
  25. 25.Best estimate of 424 + 687? (a) 1100 (b) 900 (c) 1300
  26. 26.Best estimate of 432 + 712? (a) 1100 (b) 1300 (c) 900
  27. 27.Best estimate of 174 + 705? (a) 700 (b) 900 (c) 1100
  28. 28.Best estimate of 273 + 412? (a) 700 (b) 500 (c) 900
  29. 29.Best estimate of 418 + 185? (a) 400 (b) 600 (c) 800
  30. 30.Best estimate of 703 + 845? (a) 1300 (b) 1500 (c) 1700
  31. 31.Best estimate of 56 × 77? (a) 48000 (b) 480 (c) 4800
  32. 32.Best estimate of 437 + 563? (a) 1200 (b) 800 (c) 1000
  33. 33.Best estimate of 36 × 72? (a) 2800 (b) 280 (c) 28000
  34. 34.Best estimate of 305 + 539? (a) 800 (b) 600 (c) 1000
  35. 35.Best estimate of 445 + 559? (a) 800 (b) 1200 (c) 1000
  36. 36.Best estimate of 26 × 68? (a) 2100 (b) 21000 (c) 210
  37. 37.Best estimate of 82 × 46? (a) 400 (b) 4000 (c) 40000
  38. 38.Best estimate of 96 × 74? (a) 70000 (b) 700 (c) 7000
  39. 39.Best estimate of 597 + 259? (a) 1100 (b) 700 (c) 900
  40. 40.Best estimate of 557 + 680? (a) 1100 (b) 1300 (c) 1500

Answer key

  1. 900
  2. 1200
  3. 800
  4. 900
  5. 1400
  6. 1300
  7. 1800
  8. 900
  9. 600
  10. 4900
  11. 1200
  12. 800
  13. 3000
  14. 1500
  15. 900
  16. 800
  17. 1800
  18. 1500
  19. 8100
  20. 3000
  21. 1200
  22. 1400
  23. 2400
  24. 700
  25. 1100
  26. 1100
  27. 900
  28. 700
  29. 600
  30. 1500
  31. 4800
  32. 1000
  33. 2800
  34. 800
  35. 1000
  36. 2100
  37. 4000
  38. 7000
  39. 900
  40. 1300

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