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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 854 · 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 16 × 47? (a) 10000 (b) 1000 (c) 100
  2. 2.Best estimate of 537 + 120? (a) 600 (b) 800 (c) 400
  3. 3.Best estimate of 510 + 256? (a) 600 (b) 1000 (c) 800
  4. 4.Best estimate of 51 × 96? (a) 500 (b) 5000 (c) 50000
  5. 5.Best estimate of 369 + 553? (a) 800 (b) 1200 (c) 1000
  6. 6.Best estimate of 707 + 409? (a) 1100 (b) 1300 (c) 900
  7. 7.Best estimate of 46 × 36? (a) 200 (b) 2000 (c) 20000
  8. 8.Best estimate of 781 + 147? (a) 700 (b) 900 (c) 1100
  9. 9.Best estimate of 22 × 63? (a) 12000 (b) 1200 (c) 120
  10. 10.Best estimate of 20 × 96? (a) 200 (b) 20000 (c) 2000
  11. 11.Best estimate of 709 + 644? (a) 1500 (b) 1300 (c) 1100
  12. 12.Best estimate of 26 × 36? (a) 120 (b) 12000 (c) 1200
  13. 13.Best estimate of 488 + 810? (a) 1500 (b) 1100 (c) 1300
  14. 14.Best estimate of 453 + 710? (a) 1400 (b) 1200 (c) 1000
  15. 15.Best estimate of 673 + 710? (a) 1400 (b) 1200 (c) 1600
  16. 16.Best estimate of 86 × 20? (a) 1800 (b) 18000 (c) 180
  17. 17.Best estimate of 622 + 786? (a) 1200 (b) 1600 (c) 1400
  18. 18.Best estimate of 236 + 842? (a) 800 (b) 1200 (c) 1000
  19. 19.Best estimate of 52 × 96? (a) 500 (b) 5000 (c) 50000
  20. 20.Best estimate of 554 + 560? (a) 1400 (b) 1000 (c) 1200
  21. 21.Best estimate of 236 + 717? (a) 1100 (b) 900 (c) 700
  22. 22.Best estimate of 62 × 83? (a) 480 (b) 48000 (c) 4800
  23. 23.Best estimate of 47 × 81? (a) 400 (b) 40000 (c) 4000
  24. 24.Best estimate of 22 × 72? (a) 1400 (b) 14000 (c) 140
  25. 25.Best estimate of 78 × 49? (a) 400 (b) 40000 (c) 4000
  26. 26.Best estimate of 32 × 39? (a) 12000 (b) 120 (c) 1200
  27. 27.Best estimate of 71 × 56? (a) 42000 (b) 420 (c) 4200
  28. 28.Best estimate of 91 × 30? (a) 2700 (b) 27000 (c) 270
  29. 29.Best estimate of 195 + 477? (a) 700 (b) 900 (c) 500
  30. 30.Best estimate of 569 + 460? (a) 1100 (b) 1300 (c) 900
  31. 31.Best estimate of 49 × 21? (a) 1000 (b) 100 (c) 10000
  32. 32.Best estimate of 97 × 89? (a) 900 (b) 9000 (c) 90000
  33. 33.Best estimate of 23 × 98? (a) 20000 (b) 200 (c) 2000
  34. 34.Best estimate of 56 × 20? (a) 120 (b) 1200 (c) 12000
  35. 35.Best estimate of 832 + 147? (a) 900 (b) 1100 (c) 700
  36. 36.Best estimate of 322 + 288? (a) 600 (b) 800 (c) 400
  37. 37.Best estimate of 352 + 798? (a) 1000 (b) 1400 (c) 1200
  38. 38.Best estimate of 93 × 41? (a) 360 (b) 3600 (c) 36000
  39. 39.Best estimate of 64 × 54? (a) 3000 (b) 30000 (c) 300
  40. 40.Best estimate of 62 × 94? (a) 5400 (b) 540 (c) 54000

Answer key

  1. 1000
  2. 600
  3. 800
  4. 5000
  5. 1000
  6. 1100
  7. 2000
  8. 900
  9. 1200
  10. 2000
  11. 1300
  12. 1200
  13. 1300
  14. 1200
  15. 1400
  16. 1800
  17. 1400
  18. 1000
  19. 5000
  20. 1200
  21. 900
  22. 4800
  23. 4000
  24. 1400
  25. 4000
  26. 1200
  27. 4200
  28. 2700
  29. 700
  30. 1100
  31. 1000
  32. 9000
  33. 2000
  34. 1200
  35. 900
  36. 600
  37. 1200
  38. 3600
  39. 3000
  40. 5400

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