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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 977 · 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 862 + 631? (a) 1500 (b) 1300 (c) 1700
  2. 2.Best estimate of 423 + 354? (a) 600 (b) 1000 (c) 800
  3. 3.Best estimate of 38 × 34? (a) 1200 (b) 12000 (c) 120
  4. 4.Best estimate of 156 + 322? (a) 500 (b) 300 (c) 700
  5. 5.Best estimate of 325 + 779? (a) 1100 (b) 1300 (c) 900
  6. 6.Best estimate of 662 + 830? (a) 1700 (b) 1300 (c) 1500
  7. 7.Best estimate of 60 × 16? (a) 12000 (b) 1200 (c) 120
  8. 8.Best estimate of 242 + 660? (a) 1100 (b) 900 (c) 700
  9. 9.Best estimate of 83 × 26? (a) 24000 (b) 240 (c) 2400
  10. 10.Best estimate of 66 × 42? (a) 28000 (b) 2800 (c) 280
  11. 11.Best estimate of 727 + 187? (a) 900 (b) 1100 (c) 700
  12. 12.Best estimate of 610 + 123? (a) 900 (b) 700 (c) 500
  13. 13.Best estimate of 71 × 49? (a) 350 (b) 3500 (c) 35000
  14. 14.Best estimate of 446 + 617? (a) 1000 (b) 1200 (c) 800
  15. 15.Best estimate of 77 × 50? (a) 4000 (b) 40000 (c) 400
  16. 16.Best estimate of 153 + 144? (a) 100 (b) 300 (c) 500
  17. 17.Best estimate of 549 + 147? (a) 600 (b) 400 (c) 800
  18. 18.Best estimate of 596 + 377? (a) 1200 (b) 800 (c) 1000
  19. 19.Best estimate of 23 × 82? (a) 16000 (b) 160 (c) 1600
  20. 20.Best estimate of 97 × 29? (a) 30000 (b) 3000 (c) 300
  21. 21.Best estimate of 13 × 31? (a) 300 (b) 3000 (c) 30
  22. 22.Best estimate of 616 + 303? (a) 900 (b) 1100 (c) 700
  23. 23.Best estimate of 19 × 76? (a) 16000 (b) 1600 (c) 160
  24. 24.Best estimate of 443 + 121? (a) 700 (b) 500 (c) 300
  25. 25.Best estimate of 273 + 166? (a) 500 (b) 300 (c) 700
  26. 26.Best estimate of 382 + 241? (a) 800 (b) 600 (c) 400
  27. 27.Best estimate of 358 + 655? (a) 1300 (b) 900 (c) 1100
  28. 28.Best estimate of 346 + 610? (a) 700 (b) 900 (c) 1100
  29. 29.Best estimate of 328 + 266? (a) 800 (b) 600 (c) 400
  30. 30.Best estimate of 772 + 195? (a) 1000 (b) 1200 (c) 800
  31. 31.Best estimate of 159 + 176? (a) 600 (b) 400 (c) 200
  32. 32.Best estimate of 22 × 98? (a) 20000 (b) 2000 (c) 200
  33. 33.Best estimate of 395 + 225? (a) 600 (b) 800 (c) 400
  34. 34.Best estimate of 76 × 12? (a) 8000 (b) 800 (c) 80
  35. 35.Best estimate of 78 × 58? (a) 480 (b) 48000 (c) 4800
  36. 36.Best estimate of 70 × 13? (a) 700 (b) 7000 (c) 70
  37. 37.Best estimate of 273 + 157? (a) 500 (b) 300 (c) 700
  38. 38.Best estimate of 841 + 268? (a) 1100 (b) 1300 (c) 900
  39. 39.Best estimate of 87 × 87? (a) 8100 (b) 81000 (c) 810
  40. 40.Best estimate of 202 + 671? (a) 900 (b) 700 (c) 1100

Answer key

  1. 1500
  2. 800
  3. 1200
  4. 500
  5. 1100
  6. 1500
  7. 1200
  8. 900
  9. 2400
  10. 2800
  11. 900
  12. 700
  13. 3500
  14. 1000
  15. 4000
  16. 300
  17. 600
  18. 1000
  19. 1600
  20. 3000
  21. 300
  22. 900
  23. 1600
  24. 500
  25. 500
  26. 600
  27. 1100
  28. 900
  29. 600
  30. 1000
  31. 400
  32. 2000
  33. 600
  34. 800
  35. 4800
  36. 700
  37. 500
  38. 1100
  39. 8100
  40. 900

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