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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 431 · 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 680 + 309? (a) 1200 (b) 1000 (c) 800
  2. 2.Best estimate of 34 × 98? (a) 3000 (b) 30000 (c) 300
  3. 3.Best estimate of 46 × 62? (a) 300 (b) 3000 (c) 30000
  4. 4.Best estimate of 739 + 789? (a) 1700 (b) 1500 (c) 1300
  5. 5.Best estimate of 40 × 58? (a) 24000 (b) 2400 (c) 240
  6. 6.Best estimate of 673 + 676? (a) 1600 (b) 1200 (c) 1400
  7. 7.Best estimate of 93 × 93? (a) 8100 (b) 81000 (c) 810
  8. 8.Best estimate of 558 + 493? (a) 900 (b) 1300 (c) 1100
  9. 9.Best estimate of 36 × 28? (a) 12000 (b) 1200 (c) 120
  10. 10.Best estimate of 53 × 32? (a) 1500 (b) 15000 (c) 150
  11. 11.Best estimate of 598 + 130? (a) 700 (b) 500 (c) 900
  12. 12.Best estimate of 162 + 831? (a) 1200 (b) 1000 (c) 800
  13. 13.Best estimate of 17 × 36? (a) 80 (b) 800 (c) 8000
  14. 14.Best estimate of 66 × 32? (a) 2100 (b) 210 (c) 21000
  15. 15.Best estimate of 594 + 701? (a) 1100 (b) 1500 (c) 1300
  16. 16.Best estimate of 58 × 76? (a) 4800 (b) 48000 (c) 480
  17. 17.Best estimate of 630 + 870? (a) 1300 (b) 1500 (c) 1700
  18. 18.Best estimate of 80 × 19? (a) 1600 (b) 16000 (c) 160
  19. 19.Best estimate of 758 + 564? (a) 1400 (b) 1200 (c) 1600
  20. 20.Best estimate of 525 + 673? (a) 1200 (b) 1400 (c) 1000
  21. 21.Best estimate of 571 + 411? (a) 800 (b) 1000 (c) 1200
  22. 22.Best estimate of 87 × 22? (a) 18000 (b) 180 (c) 1800
  23. 23.Best estimate of 13 × 66? (a) 700 (b) 7000 (c) 70
  24. 24.Best estimate of 513 + 790? (a) 1300 (b) 1100 (c) 1500
  25. 25.Best estimate of 77 × 46? (a) 400 (b) 40000 (c) 4000
  26. 26.Best estimate of 69 × 33? (a) 210 (b) 21000 (c) 2100
  27. 27.Best estimate of 97 × 83? (a) 80000 (b) 800 (c) 8000
  28. 28.Best estimate of 580 + 127? (a) 500 (b) 900 (c) 700
  29. 29.Best estimate of 770 + 181? (a) 1200 (b) 1000 (c) 800
  30. 30.Best estimate of 86 × 38? (a) 36000 (b) 3600 (c) 360
  31. 31.Best estimate of 483 + 191? (a) 700 (b) 900 (c) 500
  32. 32.Best estimate of 62 × 88? (a) 5400 (b) 54000 (c) 540
  33. 33.Best estimate of 772 + 265? (a) 900 (b) 1300 (c) 1100
  34. 34.Best estimate of 42 × 63? (a) 2400 (b) 240 (c) 24000
  35. 35.Best estimate of 376 + 446? (a) 600 (b) 800 (c) 1000
  36. 36.Best estimate of 30 × 56? (a) 1800 (b) 18000 (c) 180
  37. 37.Best estimate of 86 × 48? (a) 4500 (b) 450 (c) 45000
  38. 38.Best estimate of 56 × 72? (a) 42000 (b) 4200 (c) 420
  39. 39.Best estimate of 172 + 769? (a) 1200 (b) 1000 (c) 800
  40. 40.Best estimate of 66 × 18? (a) 14000 (b) 140 (c) 1400

Answer key

  1. 1000
  2. 3000
  3. 3000
  4. 1500
  5. 2400
  6. 1400
  7. 8100
  8. 1100
  9. 1200
  10. 1500
  11. 700
  12. 1000
  13. 800
  14. 2100
  15. 1300
  16. 4800
  17. 1500
  18. 1600
  19. 1400
  20. 1200
  21. 1000
  22. 1800
  23. 700
  24. 1300
  25. 4000
  26. 2100
  27. 8000
  28. 700
  29. 1000
  30. 3600
  31. 700
  32. 5400
  33. 1100
  34. 2400
  35. 800
  36. 1800
  37. 4500
  38. 4200
  39. 1000
  40. 1400

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