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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 729 · 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 128 + 348? (a) 600 (b) 200 (c) 400
  2. 2.Best estimate of 298 + 278? (a) 600 (b) 400 (c) 800
  3. 3.Best estimate of 44 × 89? (a) 3600 (b) 360 (c) 36000
  4. 4.Best estimate of 58 × 82? (a) 48000 (b) 480 (c) 4800
  5. 5.Best estimate of 54 × 48? (a) 250 (b) 2500 (c) 25000
  6. 6.Best estimate of 16 × 16? (a) 4000 (b) 40 (c) 400
  7. 7.Best estimate of 27 × 76? (a) 24000 (b) 2400 (c) 240
  8. 8.Best estimate of 517 + 472? (a) 1000 (b) 1200 (c) 800
  9. 9.Best estimate of 734 + 575? (a) 1300 (b) 1500 (c) 1100
  10. 10.Best estimate of 779 + 346? (a) 1100 (b) 900 (c) 1300
  11. 11.Best estimate of 477 + 171? (a) 700 (b) 500 (c) 900
  12. 12.Best estimate of 539 + 561? (a) 1300 (b) 1100 (c) 900
  13. 13.Best estimate of 542 + 621? (a) 1100 (b) 900 (c) 1300
  14. 14.Best estimate of 27 × 84? (a) 2400 (b) 24000 (c) 240
  15. 15.Best estimate of 31 × 47? (a) 15000 (b) 150 (c) 1500
  16. 16.Best estimate of 37 × 96? (a) 4000 (b) 40000 (c) 400
  17. 17.Best estimate of 143 + 277? (a) 400 (b) 600 (c) 200
  18. 18.Best estimate of 533 + 493? (a) 1200 (b) 800 (c) 1000
  19. 19.Best estimate of 832 + 516? (a) 1300 (b) 1500 (c) 1100
  20. 20.Best estimate of 52 × 24? (a) 100 (b) 10000 (c) 1000
  21. 21.Best estimate of 148 + 405? (a) 700 (b) 300 (c) 500
  22. 22.Best estimate of 698 + 766? (a) 1500 (b) 1700 (c) 1300
  23. 23.Best estimate of 49 × 12? (a) 5000 (b) 500 (c) 50
  24. 24.Best estimate of 426 + 751? (a) 1400 (b) 1000 (c) 1200
  25. 25.Best estimate of 20 × 41? (a) 800 (b) 8000 (c) 80
  26. 26.Best estimate of 200 + 777? (a) 800 (b) 1200 (c) 1000
  27. 27.Best estimate of 73 × 31? (a) 2100 (b) 21000 (c) 210
  28. 28.Best estimate of 82 × 20? (a) 160 (b) 16000 (c) 1600
  29. 29.Best estimate of 413 + 341? (a) 900 (b) 500 (c) 700
  30. 30.Best estimate of 465 + 745? (a) 1400 (b) 1200 (c) 1000
  31. 31.Best estimate of 27 × 13? (a) 300 (b) 30 (c) 3000
  32. 32.Best estimate of 282 + 546? (a) 600 (b) 1000 (c) 800
  33. 33.Best estimate of 77 × 34? (a) 2400 (b) 24000 (c) 240
  34. 34.Best estimate of 42 × 29? (a) 1200 (b) 120 (c) 12000
  35. 35.Best estimate of 364 + 141? (a) 700 (b) 500 (c) 300
  36. 36.Best estimate of 624 + 809? (a) 1400 (b) 1600 (c) 1200
  37. 37.Best estimate of 244 + 193? (a) 400 (b) 600 (c) 200
  38. 38.Best estimate of 69 × 57? (a) 42000 (b) 420 (c) 4200
  39. 39.Best estimate of 68 × 16? (a) 140 (b) 14000 (c) 1400
  40. 40.Best estimate of 14 × 96? (a) 100 (b) 1000 (c) 10000

Answer key

  1. 400
  2. 600
  3. 3600
  4. 4800
  5. 2500
  6. 400
  7. 2400
  8. 1000
  9. 1300
  10. 1100
  11. 700
  12. 1100
  13. 1100
  14. 2400
  15. 1500
  16. 4000
  17. 400
  18. 1000
  19. 1300
  20. 1000
  21. 500
  22. 1500
  23. 500
  24. 1200
  25. 800
  26. 1000
  27. 2100
  28. 1600
  29. 700
  30. 1200
  31. 300
  32. 800
  33. 2400
  34. 1200
  35. 500
  36. 1400
  37. 400
  38. 4200
  39. 1400
  40. 1000

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