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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 619 · 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 863 + 208? (a) 1100 (b) 1300 (c) 900
  2. 2.Best estimate of 36 × 34? (a) 12000 (b) 1200 (c) 120
  3. 3.Best estimate of 16 × 39? (a) 8000 (b) 80 (c) 800
  4. 4.Best estimate of 64 × 34? (a) 180 (b) 18000 (c) 1800
  5. 5.Best estimate of 12 × 96? (a) 100 (b) 10000 (c) 1000
  6. 6.Best estimate of 648 + 291? (a) 900 (b) 700 (c) 1100
  7. 7.Best estimate of 66 × 66? (a) 490 (b) 4900 (c) 49000
  8. 8.Best estimate of 30 × 28? (a) 900 (b) 9000 (c) 90
  9. 9.Best estimate of 599 + 536? (a) 900 (b) 1300 (c) 1100
  10. 10.Best estimate of 26 × 79? (a) 2400 (b) 24000 (c) 240
  11. 11.Best estimate of 228 + 314? (a) 700 (b) 500 (c) 300
  12. 12.Best estimate of 27 × 47? (a) 15000 (b) 150 (c) 1500
  13. 13.Best estimate of 44 × 31? (a) 1200 (b) 120 (c) 12000
  14. 14.Best estimate of 19 × 86? (a) 180 (b) 1800 (c) 18000
  15. 15.Best estimate of 480 + 228? (a) 500 (b) 700 (c) 900
  16. 16.Best estimate of 80 × 76? (a) 64000 (b) 6400 (c) 640
  17. 17.Best estimate of 40 × 92? (a) 360 (b) 36000 (c) 3600
  18. 18.Best estimate of 294 + 767? (a) 1100 (b) 900 (c) 1300
  19. 19.Best estimate of 24 × 43? (a) 800 (b) 8000 (c) 80
  20. 20.Best estimate of 57 × 44? (a) 24000 (b) 2400 (c) 240
  21. 21.Best estimate of 256 + 468? (a) 800 (b) 600 (c) 1000
  22. 22.Best estimate of 88 × 49? (a) 45000 (b) 4500 (c) 450
  23. 23.Best estimate of 686 + 469? (a) 1000 (b) 1200 (c) 1400
  24. 24.Best estimate of 36 × 27? (a) 12000 (b) 1200 (c) 120
  25. 25.Best estimate of 427 + 202? (a) 800 (b) 400 (c) 600
  26. 26.Best estimate of 92 × 30? (a) 270 (b) 2700 (c) 27000
  27. 27.Best estimate of 31 × 14? (a) 300 (b) 30 (c) 3000
  28. 28.Best estimate of 66 × 71? (a) 49000 (b) 490 (c) 4900
  29. 29.Best estimate of 219 + 319? (a) 500 (b) 700 (c) 300
  30. 30.Best estimate of 12 × 98? (a) 100 (b) 10000 (c) 1000
  31. 31.Best estimate of 86 × 60? (a) 54000 (b) 5400 (c) 540
  32. 32.Best estimate of 38 × 52? (a) 2000 (b) 200 (c) 20000
  33. 33.Best estimate of 34 × 37? (a) 120 (b) 1200 (c) 12000
  34. 34.Best estimate of 624 + 238? (a) 600 (b) 1000 (c) 800
  35. 35.Best estimate of 89 × 51? (a) 45000 (b) 450 (c) 4500
  36. 36.Best estimate of 399 + 707? (a) 1300 (b) 900 (c) 1100
  37. 37.Best estimate of 853 + 294? (a) 1000 (b) 1200 (c) 1400
  38. 38.Best estimate of 547 + 787? (a) 1100 (b) 1300 (c) 1500
  39. 39.Best estimate of 803 + 266? (a) 1100 (b) 1300 (c) 900
  40. 40.Best estimate of 40 × 58? (a) 2400 (b) 24000 (c) 240

Answer key

  1. 1100
  2. 1200
  3. 800
  4. 1800
  5. 1000
  6. 900
  7. 4900
  8. 900
  9. 1100
  10. 2400
  11. 500
  12. 1500
  13. 1200
  14. 1800
  15. 700
  16. 6400
  17. 3600
  18. 1100
  19. 800
  20. 2400
  21. 800
  22. 4500
  23. 1200
  24. 1200
  25. 600
  26. 2700
  27. 300
  28. 4900
  29. 500
  30. 1000
  31. 5400
  32. 2000
  33. 1200
  34. 800
  35. 4500
  36. 1100
  37. 1200
  38. 1300
  39. 1100
  40. 2400

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