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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 881 · 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 634 + 792? (a) 1400 (b) 1600 (c) 1200
  2. 2.Best estimate of 765 + 222? (a) 800 (b) 1200 (c) 1000
  3. 3.Best estimate of 170 + 777? (a) 800 (b) 1200 (c) 1000
  4. 4.Best estimate of 504 + 497? (a) 800 (b) 1000 (c) 1200
  5. 5.Best estimate of 616 + 643? (a) 1200 (b) 1400 (c) 1000
  6. 6.Best estimate of 91 × 60? (a) 540 (b) 54000 (c) 5400
  7. 7.Best estimate of 772 + 826? (a) 1600 (b) 1400 (c) 1800
  8. 8.Best estimate of 46 × 52? (a) 25000 (b) 250 (c) 2500
  9. 9.Best estimate of 575 + 451? (a) 1100 (b) 900 (c) 1300
  10. 10.Best estimate of 49 × 32? (a) 1500 (b) 15000 (c) 150
  11. 11.Best estimate of 26 × 64? (a) 180 (b) 18000 (c) 1800
  12. 12.Best estimate of 803 + 714? (a) 1500 (b) 1700 (c) 1300
  13. 13.Best estimate of 456 + 403? (a) 1100 (b) 700 (c) 900
  14. 14.Best estimate of 174 + 769? (a) 1000 (b) 800 (c) 1200
  15. 15.Best estimate of 17 × 74? (a) 1400 (b) 14000 (c) 140
  16. 16.Best estimate of 57 × 32? (a) 1800 (b) 18000 (c) 180
  17. 17.Best estimate of 453 + 208? (a) 900 (b) 500 (c) 700
  18. 18.Best estimate of 32 × 87? (a) 2700 (b) 270 (c) 27000
  19. 19.Best estimate of 87 × 46? (a) 4500 (b) 450 (c) 45000
  20. 20.Best estimate of 49 × 30? (a) 150 (b) 1500 (c) 15000
  21. 21.Best estimate of 89 × 24? (a) 18000 (b) 180 (c) 1800
  22. 22.Best estimate of 252 + 201? (a) 300 (b) 500 (c) 700
  23. 23.Best estimate of 76 × 60? (a) 48000 (b) 4800 (c) 480
  24. 24.Best estimate of 84 × 60? (a) 48000 (b) 4800 (c) 480
  25. 25.Best estimate of 96 × 56? (a) 6000 (b) 60000 (c) 600
  26. 26.Best estimate of 318 + 627? (a) 1100 (b) 700 (c) 900
  27. 27.Best estimate of 30 × 81? (a) 240 (b) 24000 (c) 2400
  28. 28.Best estimate of 16 × 72? (a) 1400 (b) 14000 (c) 140
  29. 29.Best estimate of 52 × 68? (a) 350 (b) 35000 (c) 3500
  30. 30.Best estimate of 701 + 153? (a) 900 (b) 1100 (c) 700
  31. 31.Best estimate of 508 + 232? (a) 500 (b) 900 (c) 700
  32. 32.Best estimate of 214 + 166? (a) 200 (b) 600 (c) 400
  33. 33.Best estimate of 645 + 460? (a) 1300 (b) 1100 (c) 900
  34. 34.Best estimate of 738 + 775? (a) 1700 (b) 1500 (c) 1300
  35. 35.Best estimate of 23 × 41? (a) 80 (b) 8000 (c) 800
  36. 36.Best estimate of 324 + 187? (a) 700 (b) 300 (c) 500
  37. 37.Best estimate of 347 + 465? (a) 1000 (b) 800 (c) 600
  38. 38.Best estimate of 507 + 816? (a) 1100 (b) 1500 (c) 1300
  39. 39.Best estimate of 96 × 21? (a) 2000 (b) 20000 (c) 200
  40. 40.Best estimate of 715 + 778? (a) 1700 (b) 1300 (c) 1500

Answer key

  1. 1400
  2. 1000
  3. 1000
  4. 1000
  5. 1200
  6. 5400
  7. 1600
  8. 2500
  9. 1100
  10. 1500
  11. 1800
  12. 1500
  13. 900
  14. 1000
  15. 1400
  16. 1800
  17. 700
  18. 2700
  19. 4500
  20. 1500
  21. 1800
  22. 500
  23. 4800
  24. 4800
  25. 6000
  26. 900
  27. 2400
  28. 1400
  29. 3500
  30. 900
  31. 700
  32. 400
  33. 1100
  34. 1500
  35. 800
  36. 500
  37. 800
  38. 1300
  39. 2000
  40. 1500

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