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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 208 · 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 22 × 14? (a) 20 (b) 2000 (c) 200
  2. 2.Best estimate of 596 + 477? (a) 1100 (b) 900 (c) 1300
  3. 3.Best estimate of 79 × 37? (a) 3200 (b) 320 (c) 32000
  4. 4.Best estimate of 14 × 49? (a) 500 (b) 50 (c) 5000
  5. 5.Best estimate of 48 × 36? (a) 200 (b) 2000 (c) 20000
  6. 6.Best estimate of 151 + 772? (a) 1000 (b) 1200 (c) 800
  7. 7.Best estimate of 39 × 59? (a) 2400 (b) 24000 (c) 240
  8. 8.Best estimate of 70 × 61? (a) 42000 (b) 4200 (c) 420
  9. 9.Best estimate of 337 + 762? (a) 900 (b) 1100 (c) 1300
  10. 10.Best estimate of 428 + 629? (a) 1200 (b) 1000 (c) 800
  11. 11.Best estimate of 670 + 495? (a) 1000 (b) 1400 (c) 1200
  12. 12.Best estimate of 94 × 59? (a) 54000 (b) 540 (c) 5400
  13. 13.Best estimate of 47 × 24? (a) 1000 (b) 100 (c) 10000
  14. 14.Best estimate of 58 × 31? (a) 18000 (b) 180 (c) 1800
  15. 15.Best estimate of 595 + 523? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 152 + 546? (a) 500 (b) 900 (c) 700
  17. 17.Best estimate of 74 × 18? (a) 14000 (b) 140 (c) 1400
  18. 18.Best estimate of 29 × 60? (a) 1800 (b) 180 (c) 18000
  19. 19.Best estimate of 714 + 707? (a) 1400 (b) 1600 (c) 1200
  20. 20.Best estimate of 27 × 89? (a) 2700 (b) 270 (c) 27000
  21. 21.Best estimate of 22 × 44? (a) 8000 (b) 80 (c) 800
  22. 22.Best estimate of 86 × 92? (a) 8100 (b) 81000 (c) 810
  23. 23.Best estimate of 251 + 831? (a) 900 (b) 1100 (c) 1300
  24. 24.Best estimate of 17 × 57? (a) 120 (b) 1200 (c) 12000
  25. 25.Best estimate of 790 + 599? (a) 1200 (b) 1400 (c) 1600
  26. 26.Best estimate of 190 + 377? (a) 800 (b) 600 (c) 400
  27. 27.Best estimate of 21 × 26? (a) 6000 (b) 600 (c) 60
  28. 28.Best estimate of 835 + 620? (a) 1200 (b) 1600 (c) 1400
  29. 29.Best estimate of 94 × 48? (a) 4500 (b) 450 (c) 45000
  30. 30.Best estimate of 184 + 241? (a) 200 (b) 400 (c) 600
  31. 31.Best estimate of 80 × 60? (a) 48000 (b) 4800 (c) 480
  32. 32.Best estimate of 67 × 36? (a) 28000 (b) 280 (c) 2800
  33. 33.Best estimate of 29 × 26? (a) 90 (b) 900 (c) 9000
  34. 34.Best estimate of 520 + 801? (a) 1100 (b) 1300 (c) 1500
  35. 35.Best estimate of 77 × 86? (a) 72000 (b) 7200 (c) 720
  36. 36.Best estimate of 298 + 716? (a) 1000 (b) 800 (c) 1200
  37. 37.Best estimate of 528 + 437? (a) 1100 (b) 700 (c) 900
  38. 38.Best estimate of 76 × 64? (a) 4800 (b) 480 (c) 48000
  39. 39.Best estimate of 24 × 46? (a) 10000 (b) 1000 (c) 100
  40. 40.Best estimate of 76 × 56? (a) 480 (b) 4800 (c) 48000

Answer key

  1. 200
  2. 1100
  3. 3200
  4. 500
  5. 2000
  6. 1000
  7. 2400
  8. 4200
  9. 1100
  10. 1000
  11. 1200
  12. 5400
  13. 1000
  14. 1800
  15. 1100
  16. 700
  17. 1400
  18. 1800
  19. 1400
  20. 2700
  21. 800
  22. 8100
  23. 1100
  24. 1200
  25. 1400
  26. 600
  27. 600
  28. 1400
  29. 4500
  30. 400
  31. 4800
  32. 2800
  33. 900
  34. 1300
  35. 7200
  36. 1000
  37. 900
  38. 4800
  39. 1000
  40. 4800

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