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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 571 · 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 66 × 87? (a) 6300 (b) 63000 (c) 630
  2. 2.Best estimate of 251 + 204? (a) 700 (b) 500 (c) 300
  3. 3.Best estimate of 644 + 743? (a) 1300 (b) 1500 (c) 1100
  4. 4.Best estimate of 657 + 252? (a) 1000 (b) 800 (c) 1200
  5. 5.Best estimate of 20 × 34? (a) 6000 (b) 60 (c) 600
  6. 6.Best estimate of 790 + 370? (a) 1000 (b) 1200 (c) 1400
  7. 7.Best estimate of 53 × 96? (a) 5000 (b) 50000 (c) 500
  8. 8.Best estimate of 173 + 713? (a) 700 (b) 1100 (c) 900
  9. 9.Best estimate of 63 × 40? (a) 240 (b) 2400 (c) 24000
  10. 10.Best estimate of 62 × 59? (a) 36000 (b) 360 (c) 3600
  11. 11.Best estimate of 66 × 58? (a) 4200 (b) 42000 (c) 420
  12. 12.Best estimate of 364 + 345? (a) 500 (b) 900 (c) 700
  13. 13.Best estimate of 665 + 126? (a) 1000 (b) 600 (c) 800
  14. 14.Best estimate of 232 + 445? (a) 800 (b) 600 (c) 400
  15. 15.Best estimate of 361 + 305? (a) 700 (b) 900 (c) 500
  16. 16.Best estimate of 26 × 66? (a) 210 (b) 2100 (c) 21000
  17. 17.Best estimate of 130 + 281? (a) 400 (b) 600 (c) 200
  18. 18.Best estimate of 19 × 66? (a) 1400 (b) 14000 (c) 140
  19. 19.Best estimate of 634 + 131? (a) 700 (b) 500 (c) 900
  20. 20.Best estimate of 22 × 46? (a) 1000 (b) 10000 (c) 100
  21. 21.Best estimate of 56 × 22? (a) 1200 (b) 12000 (c) 120
  22. 22.Best estimate of 795 + 262? (a) 1100 (b) 900 (c) 1300
  23. 23.Best estimate of 90 × 43? (a) 360 (b) 36000 (c) 3600
  24. 24.Best estimate of 12 × 86? (a) 900 (b) 90 (c) 9000
  25. 25.Best estimate of 88 × 86? (a) 810 (b) 81000 (c) 8100
  26. 26.Best estimate of 667 + 381? (a) 900 (b) 1300 (c) 1100
  27. 27.Best estimate of 291 + 284? (a) 800 (b) 400 (c) 600
  28. 28.Best estimate of 303 + 726? (a) 1000 (b) 800 (c) 1200
  29. 29.Best estimate of 66 × 52? (a) 350 (b) 35000 (c) 3500
  30. 30.Best estimate of 66 × 71? (a) 4900 (b) 49000 (c) 490
  31. 31.Best estimate of 27 × 37? (a) 1200 (b) 12000 (c) 120
  32. 32.Best estimate of 267 + 804? (a) 1100 (b) 900 (c) 1300
  33. 33.Best estimate of 704 + 315? (a) 1200 (b) 800 (c) 1000
  34. 34.Best estimate of 14 × 53? (a) 50 (b) 5000 (c) 500
  35. 35.Best estimate of 86 × 66? (a) 63000 (b) 630 (c) 6300
  36. 36.Best estimate of 12 × 96? (a) 1000 (b) 10000 (c) 100
  37. 37.Best estimate of 684 + 203? (a) 1100 (b) 700 (c) 900
  38. 38.Best estimate of 535 + 729? (a) 1200 (b) 1400 (c) 1000
  39. 39.Best estimate of 98 × 24? (a) 200 (b) 20000 (c) 2000
  40. 40.Best estimate of 49 × 17? (a) 1000 (b) 100 (c) 10000

Answer key

  1. 6300
  2. 500
  3. 1300
  4. 1000
  5. 600
  6. 1200
  7. 5000
  8. 900
  9. 2400
  10. 3600
  11. 4200
  12. 700
  13. 800
  14. 600
  15. 700
  16. 2100
  17. 400
  18. 1400
  19. 700
  20. 1000
  21. 1200
  22. 1100
  23. 3600
  24. 900
  25. 8100
  26. 1100
  27. 600
  28. 1000
  29. 3500
  30. 4900
  31. 1200
  32. 1100
  33. 1000
  34. 500
  35. 6300
  36. 1000
  37. 900
  38. 1200
  39. 2000
  40. 1000

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