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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 749 · 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 648 + 631? (a) 1200 (b) 1000 (c) 1400
  2. 2.Best estimate of 43 × 60? (a) 24000 (b) 2400 (c) 240
  3. 3.Best estimate of 706 + 679? (a) 1600 (b) 1200 (c) 1400
  4. 4.Best estimate of 52 × 17? (a) 10000 (b) 100 (c) 1000
  5. 5.Best estimate of 78 × 47? (a) 4000 (b) 400 (c) 40000
  6. 6.Best estimate of 96 × 52? (a) 5000 (b) 50000 (c) 500
  7. 7.Best estimate of 607 + 523? (a) 1300 (b) 1100 (c) 900
  8. 8.Best estimate of 87 × 36? (a) 360 (b) 3600 (c) 36000
  9. 9.Best estimate of 12 × 98? (a) 10000 (b) 1000 (c) 100
  10. 10.Best estimate of 475 + 317? (a) 600 (b) 800 (c) 1000
  11. 11.Best estimate of 56 × 93? (a) 540 (b) 54000 (c) 5400
  12. 12.Best estimate of 26 × 98? (a) 3000 (b) 30000 (c) 300
  13. 13.Best estimate of 66 × 79? (a) 560 (b) 56000 (c) 5600
  14. 14.Best estimate of 191 + 874? (a) 1300 (b) 1100 (c) 900
  15. 15.Best estimate of 139 + 465? (a) 600 (b) 400 (c) 800
  16. 16.Best estimate of 751 + 322? (a) 900 (b) 1300 (c) 1100
  17. 17.Best estimate of 141 + 805? (a) 900 (b) 700 (c) 1100
  18. 18.Best estimate of 64 × 93? (a) 540 (b) 5400 (c) 54000
  19. 19.Best estimate of 156 + 415? (a) 800 (b) 400 (c) 600
  20. 20.Best estimate of 501 + 630? (a) 1300 (b) 900 (c) 1100
  21. 21.Best estimate of 42 × 76? (a) 3200 (b) 320 (c) 32000
  22. 22.Best estimate of 33 × 73? (a) 210 (b) 2100 (c) 21000
  23. 23.Best estimate of 19 × 46? (a) 100 (b) 1000 (c) 10000
  24. 24.Best estimate of 423 + 291? (a) 500 (b) 900 (c) 700
  25. 25.Best estimate of 348 + 330? (a) 800 (b) 600 (c) 400
  26. 26.Best estimate of 491 + 791? (a) 1500 (b) 1300 (c) 1100
  27. 27.Best estimate of 53 × 87? (a) 450 (b) 4500 (c) 45000
  28. 28.Best estimate of 342 + 300? (a) 600 (b) 400 (c) 800
  29. 29.Best estimate of 519 + 719? (a) 1000 (b) 1400 (c) 1200
  30. 30.Best estimate of 331 + 813? (a) 1300 (b) 900 (c) 1100
  31. 31.Best estimate of 729 + 176? (a) 1100 (b) 700 (c) 900
  32. 32.Best estimate of 430 + 304? (a) 700 (b) 500 (c) 900
  33. 33.Best estimate of 41 × 59? (a) 24000 (b) 2400 (c) 240
  34. 34.Best estimate of 27 × 71? (a) 2100 (b) 21000 (c) 210
  35. 35.Best estimate of 37 × 41? (a) 1600 (b) 16000 (c) 160
  36. 36.Best estimate of 216 + 355? (a) 800 (b) 600 (c) 400
  37. 37.Best estimate of 298 + 551? (a) 1100 (b) 900 (c) 700
  38. 38.Best estimate of 164 + 310? (a) 500 (b) 300 (c) 700
  39. 39.Best estimate of 23 × 88? (a) 1800 (b) 180 (c) 18000
  40. 40.Best estimate of 52 × 36? (a) 200 (b) 2000 (c) 20000

Answer key

  1. 1200
  2. 2400
  3. 1400
  4. 1000
  5. 4000
  6. 5000
  7. 1100
  8. 3600
  9. 1000
  10. 800
  11. 5400
  12. 3000
  13. 5600
  14. 1100
  15. 600
  16. 1100
  17. 900
  18. 5400
  19. 600
  20. 1100
  21. 3200
  22. 2100
  23. 1000
  24. 700
  25. 600
  26. 1300
  27. 4500
  28. 600
  29. 1200
  30. 1100
  31. 900
  32. 700
  33. 2400
  34. 2100
  35. 1600
  36. 600
  37. 900
  38. 500
  39. 1800
  40. 2000

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