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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 156 · 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 696 + 455? (a) 1400 (b) 1200 (c) 1000
  2. 2.Best estimate of 59 × 83? (a) 480 (b) 48000 (c) 4800
  3. 3.Best estimate of 98 × 36? (a) 40000 (b) 4000 (c) 400
  4. 4.Best estimate of 347 + 722? (a) 800 (b) 1000 (c) 1200
  5. 5.Best estimate of 61 × 40? (a) 2400 (b) 240 (c) 24000
  6. 6.Best estimate of 339 + 235? (a) 500 (b) 300 (c) 700
  7. 7.Best estimate of 57 × 30? (a) 18000 (b) 1800 (c) 180
  8. 8.Best estimate of 725 + 380? (a) 1300 (b) 1100 (c) 900
  9. 9.Best estimate of 56 × 13? (a) 6000 (b) 60 (c) 600
  10. 10.Best estimate of 296 + 874? (a) 1000 (b) 1200 (c) 1400
  11. 11.Best estimate of 315 + 695? (a) 1000 (b) 800 (c) 1200
  12. 12.Best estimate of 801 + 279? (a) 1100 (b) 900 (c) 1300
  13. 13.Best estimate of 30 × 12? (a) 300 (b) 3000 (c) 30
  14. 14.Best estimate of 62 × 47? (a) 300 (b) 30000 (c) 3000
  15. 15.Best estimate of 44 × 26? (a) 1200 (b) 12000 (c) 120
  16. 16.Best estimate of 573 + 327? (a) 900 (b) 700 (c) 1100
  17. 17.Best estimate of 23 × 38? (a) 80 (b) 8000 (c) 800
  18. 18.Best estimate of 414 + 622? (a) 1000 (b) 1200 (c) 800
  19. 19.Best estimate of 16 × 63? (a) 12000 (b) 1200 (c) 120
  20. 20.Best estimate of 159 + 125? (a) 300 (b) 100 (c) 500
  21. 21.Best estimate of 832 + 682? (a) 1300 (b) 1700 (c) 1500
  22. 22.Best estimate of 534 + 201? (a) 900 (b) 700 (c) 500
  23. 23.Best estimate of 86 × 16? (a) 180 (b) 18000 (c) 1800
  24. 24.Best estimate of 30 × 97? (a) 300 (b) 30000 (c) 3000
  25. 25.Best estimate of 50 × 56? (a) 300 (b) 3000 (c) 30000
  26. 26.Best estimate of 743 + 471? (a) 1400 (b) 1200 (c) 1000
  27. 27.Best estimate of 22 × 36? (a) 8000 (b) 80 (c) 800
  28. 28.Best estimate of 749 + 151? (a) 1100 (b) 700 (c) 900
  29. 29.Best estimate of 125 + 855? (a) 1000 (b) 1200 (c) 800
  30. 30.Best estimate of 231 + 473? (a) 500 (b) 900 (c) 700
  31. 31.Best estimate of 17 × 13? (a) 200 (b) 20 (c) 2000
  32. 32.Best estimate of 48 × 96? (a) 5000 (b) 500 (c) 50000
  33. 33.Best estimate of 59 × 12? (a) 6000 (b) 600 (c) 60
  34. 34.Best estimate of 127 + 229? (a) 300 (b) 100 (c) 500
  35. 35.Best estimate of 13 × 97? (a) 10000 (b) 100 (c) 1000
  36. 36.Best estimate of 50 × 36? (a) 20000 (b) 200 (c) 2000
  37. 37.Best estimate of 12 × 28? (a) 300 (b) 3000 (c) 30
  38. 38.Best estimate of 83 × 36? (a) 320 (b) 3200 (c) 32000
  39. 39.Best estimate of 326 + 402? (a) 700 (b) 900 (c) 500
  40. 40.Best estimate of 74 × 78? (a) 5600 (b) 56000 (c) 560

Answer key

  1. 1200
  2. 4800
  3. 4000
  4. 1000
  5. 2400
  6. 500
  7. 1800
  8. 1100
  9. 600
  10. 1200
  11. 1000
  12. 1100
  13. 300
  14. 3000
  15. 1200
  16. 900
  17. 800
  18. 1000
  19. 1200
  20. 300
  21. 1500
  22. 700
  23. 1800
  24. 3000
  25. 3000
  26. 1200
  27. 800
  28. 900
  29. 1000
  30. 700
  31. 200
  32. 5000
  33. 600
  34. 300
  35. 1000
  36. 2000
  37. 300
  38. 3200
  39. 700
  40. 5600

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