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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 238 · 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 31 × 94? (a) 2700 (b) 27000 (c) 270
  2. 2.Best estimate of 294 + 598? (a) 1100 (b) 900 (c) 700
  3. 3.Best estimate of 62 × 56? (a) 360 (b) 36000 (c) 3600
  4. 4.Best estimate of 56 × 72? (a) 420 (b) 42000 (c) 4200
  5. 5.Best estimate of 617 + 594? (a) 1000 (b) 1200 (c) 1400
  6. 6.Best estimate of 873 + 337? (a) 1000 (b) 1200 (c) 1400
  7. 7.Best estimate of 37 × 21? (a) 800 (b) 8000 (c) 80
  8. 8.Best estimate of 354 + 808? (a) 1400 (b) 1200 (c) 1000
  9. 9.Best estimate of 453 + 869? (a) 1600 (b) 1400 (c) 1200
  10. 10.Best estimate of 27 × 79? (a) 240 (b) 24000 (c) 2400
  11. 11.Best estimate of 22 × 32? (a) 6000 (b) 60 (c) 600
  12. 12.Best estimate of 39 × 76? (a) 3200 (b) 32000 (c) 320
  13. 13.Best estimate of 96 × 20? (a) 200 (b) 2000 (c) 20000
  14. 14.Best estimate of 874 + 558? (a) 1300 (b) 1700 (c) 1500
  15. 15.Best estimate of 864 + 288? (a) 1200 (b) 1400 (c) 1000
  16. 16.Best estimate of 17 × 47? (a) 10000 (b) 1000 (c) 100
  17. 17.Best estimate of 63 × 27? (a) 18000 (b) 1800 (c) 180
  18. 18.Best estimate of 526 + 313? (a) 600 (b) 800 (c) 1000
  19. 19.Best estimate of 28 × 20? (a) 600 (b) 6000 (c) 60
  20. 20.Best estimate of 39 × 49? (a) 2000 (b) 200 (c) 20000
  21. 21.Best estimate of 572 + 624? (a) 1000 (b) 1400 (c) 1200
  22. 22.Best estimate of 76 × 36? (a) 32000 (b) 3200 (c) 320
  23. 23.Best estimate of 98 × 43? (a) 4000 (b) 40000 (c) 400
  24. 24.Best estimate of 36 × 22? (a) 800 (b) 8000 (c) 80
  25. 25.Best estimate of 396 + 730? (a) 900 (b) 1100 (c) 1300
  26. 26.Best estimate of 47 × 40? (a) 200 (b) 20000 (c) 2000
  27. 27.Best estimate of 94 × 53? (a) 450 (b) 45000 (c) 4500
  28. 28.Best estimate of 827 + 314? (a) 1100 (b) 1300 (c) 900
  29. 29.Best estimate of 444 + 165? (a) 600 (b) 400 (c) 800
  30. 30.Best estimate of 471 + 205? (a) 500 (b) 700 (c) 900
  31. 31.Best estimate of 69 × 67? (a) 4900 (b) 49000 (c) 490
  32. 32.Best estimate of 862 + 620? (a) 1700 (b) 1300 (c) 1500
  33. 33.Best estimate of 551 + 469? (a) 1300 (b) 900 (c) 1100
  34. 34.Best estimate of 38 × 90? (a) 3600 (b) 36000 (c) 360
  35. 35.Best estimate of 12 × 63? (a) 60 (b) 6000 (c) 600
  36. 36.Best estimate of 240 + 508? (a) 700 (b) 500 (c) 900
  37. 37.Best estimate of 370 + 214? (a) 600 (b) 400 (c) 800
  38. 38.Best estimate of 821 + 243? (a) 1000 (b) 800 (c) 1200
  39. 39.Best estimate of 17 × 93? (a) 180 (b) 18000 (c) 1800
  40. 40.Best estimate of 446 + 321? (a) 900 (b) 700 (c) 500

Answer key

  1. 2700
  2. 900
  3. 3600
  4. 4200
  5. 1200
  6. 1200
  7. 800
  8. 1200
  9. 1400
  10. 2400
  11. 600
  12. 3200
  13. 2000
  14. 1500
  15. 1200
  16. 1000
  17. 1800
  18. 800
  19. 600
  20. 2000
  21. 1200
  22. 3200
  23. 4000
  24. 800
  25. 1100
  26. 2000
  27. 4500
  28. 1100
  29. 600
  30. 700
  31. 4900
  32. 1500
  33. 1100
  34. 3600
  35. 600
  36. 700
  37. 600
  38. 1000
  39. 1800
  40. 700

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