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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 972 · 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 43 × 66? (a) 28000 (b) 280 (c) 2800
  2. 2.Best estimate of 50 × 97? (a) 50000 (b) 5000 (c) 500
  3. 3.Best estimate of 96 × 28? (a) 30000 (b) 3000 (c) 300
  4. 4.Best estimate of 96 × 32? (a) 3000 (b) 30000 (c) 300
  5. 5.Best estimate of 86 × 69? (a) 63000 (b) 6300 (c) 630
  6. 6.Best estimate of 443 + 245? (a) 600 (b) 400 (c) 800
  7. 7.Best estimate of 72 × 79? (a) 5600 (b) 560 (c) 56000
  8. 8.Best estimate of 317 + 725? (a) 1000 (b) 1200 (c) 800
  9. 9.Best estimate of 472 + 507? (a) 1200 (b) 800 (c) 1000
  10. 10.Best estimate of 58 × 89? (a) 540 (b) 54000 (c) 5400
  11. 11.Best estimate of 66 × 12? (a) 70 (b) 7000 (c) 700
  12. 12.Best estimate of 37 × 60? (a) 240 (b) 2400 (c) 24000
  13. 13.Best estimate of 22 × 13? (a) 20 (b) 2000 (c) 200
  14. 14.Best estimate of 88 × 70? (a) 6300 (b) 630 (c) 63000
  15. 15.Best estimate of 23 × 64? (a) 120 (b) 1200 (c) 12000
  16. 16.Best estimate of 325 + 167? (a) 300 (b) 500 (c) 700
  17. 17.Best estimate of 120 + 694? (a) 800 (b) 1000 (c) 600
  18. 18.Best estimate of 71 × 26? (a) 21000 (b) 210 (c) 2100
  19. 19.Best estimate of 42 × 41? (a) 160 (b) 1600 (c) 16000
  20. 20.Best estimate of 60 × 83? (a) 48000 (b) 480 (c) 4800
  21. 21.Best estimate of 64 × 57? (a) 36000 (b) 3600 (c) 360
  22. 22.Best estimate of 56 × 86? (a) 54000 (b) 5400 (c) 540
  23. 23.Best estimate of 42 × 63? (a) 240 (b) 2400 (c) 24000
  24. 24.Best estimate of 83 × 70? (a) 5600 (b) 56000 (c) 560
  25. 25.Best estimate of 478 + 236? (a) 900 (b) 500 (c) 700
  26. 26.Best estimate of 46 × 58? (a) 30000 (b) 3000 (c) 300
  27. 27.Best estimate of 29 × 89? (a) 270 (b) 27000 (c) 2700
  28. 28.Best estimate of 39 × 68? (a) 28000 (b) 280 (c) 2800
  29. 29.Best estimate of 23 × 98? (a) 2000 (b) 200 (c) 20000
  30. 30.Best estimate of 41 × 12? (a) 4000 (b) 40 (c) 400
  31. 31.Best estimate of 265 + 207? (a) 500 (b) 300 (c) 700
  32. 32.Best estimate of 71 × 88? (a) 63000 (b) 6300 (c) 630
  33. 33.Best estimate of 66 × 77? (a) 5600 (b) 560 (c) 56000
  34. 34.Best estimate of 52 × 17? (a) 100 (b) 1000 (c) 10000
  35. 35.Best estimate of 325 + 297? (a) 800 (b) 600 (c) 400
  36. 36.Best estimate of 91 × 31? (a) 2700 (b) 27000 (c) 270
  37. 37.Best estimate of 146 + 834? (a) 1100 (b) 700 (c) 900
  38. 38.Best estimate of 880 + 300? (a) 1400 (b) 1000 (c) 1200
  39. 39.Best estimate of 185 + 589? (a) 800 (b) 600 (c) 1000
  40. 40.Best estimate of 228 + 235? (a) 600 (b) 400 (c) 200

Answer key

  1. 2800
  2. 5000
  3. 3000
  4. 3000
  5. 6300
  6. 600
  7. 5600
  8. 1000
  9. 1000
  10. 5400
  11. 700
  12. 2400
  13. 200
  14. 6300
  15. 1200
  16. 500
  17. 800
  18. 2100
  19. 1600
  20. 4800
  21. 3600
  22. 5400
  23. 2400
  24. 5600
  25. 700
  26. 3000
  27. 2700
  28. 2800
  29. 2000
  30. 400
  31. 500
  32. 6300
  33. 5600
  34. 1000
  35. 600
  36. 2700
  37. 900
  38. 1200
  39. 800
  40. 400

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