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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 271 · 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 795 + 860? (a) 1700 (b) 1900 (c) 1500
  2. 2.Best estimate of 46 × 52? (a) 2500 (b) 250 (c) 25000
  3. 3.Best estimate of 38 × 77? (a) 320 (b) 3200 (c) 32000
  4. 4.Best estimate of 36 × 89? (a) 36000 (b) 360 (c) 3600
  5. 5.Best estimate of 71 × 52? (a) 35000 (b) 350 (c) 3500
  6. 6.Best estimate of 80 × 96? (a) 800 (b) 80000 (c) 8000
  7. 7.Best estimate of 536 + 834? (a) 1300 (b) 1100 (c) 1500
  8. 8.Best estimate of 489 + 331? (a) 800 (b) 600 (c) 1000
  9. 9.Best estimate of 275 + 187? (a) 500 (b) 700 (c) 300
  10. 10.Best estimate of 50 × 94? (a) 450 (b) 45000 (c) 4500
  11. 11.Best estimate of 86 × 84? (a) 720 (b) 72000 (c) 7200
  12. 12.Best estimate of 171 + 634? (a) 800 (b) 1000 (c) 600
  13. 13.Best estimate of 22 × 28? (a) 600 (b) 60 (c) 6000
  14. 14.Best estimate of 432 + 379? (a) 800 (b) 600 (c) 1000
  15. 15.Best estimate of 207 + 847? (a) 800 (b) 1200 (c) 1000
  16. 16.Best estimate of 69 × 38? (a) 280 (b) 2800 (c) 28000
  17. 17.Best estimate of 84 × 49? (a) 400 (b) 4000 (c) 40000
  18. 18.Best estimate of 33 × 98? (a) 3000 (b) 30000 (c) 300
  19. 19.Best estimate of 37 × 74? (a) 2800 (b) 28000 (c) 280
  20. 20.Best estimate of 44 × 67? (a) 2800 (b) 28000 (c) 280
  21. 21.Best estimate of 74 × 90? (a) 63000 (b) 630 (c) 6300
  22. 22.Best estimate of 96 × 59? (a) 6000 (b) 60000 (c) 600
  23. 23.Best estimate of 46 × 64? (a) 30000 (b) 300 (c) 3000
  24. 24.Best estimate of 12 × 17? (a) 200 (b) 2000 (c) 20
  25. 25.Best estimate of 43 × 83? (a) 320 (b) 32000 (c) 3200
  26. 26.Best estimate of 90 × 28? (a) 2700 (b) 270 (c) 27000
  27. 27.Best estimate of 677 + 255? (a) 1200 (b) 1000 (c) 800
  28. 28.Best estimate of 96 × 33? (a) 3000 (b) 30000 (c) 300
  29. 29.Best estimate of 490 + 388? (a) 900 (b) 700 (c) 1100
  30. 30.Best estimate of 432 + 373? (a) 1000 (b) 800 (c) 600
  31. 31.Best estimate of 36 × 36? (a) 16000 (b) 1600 (c) 160
  32. 32.Best estimate of 82 × 13? (a) 800 (b) 80 (c) 8000
  33. 33.Best estimate of 741 + 427? (a) 1300 (b) 1100 (c) 900
  34. 34.Best estimate of 40 × 94? (a) 360 (b) 3600 (c) 36000
  35. 35.Best estimate of 97 × 58? (a) 600 (b) 6000 (c) 60000
  36. 36.Best estimate of 590 + 381? (a) 1200 (b) 1000 (c) 800
  37. 37.Best estimate of 545 + 469? (a) 1000 (b) 1200 (c) 800
  38. 38.Best estimate of 23 × 36? (a) 800 (b) 8000 (c) 80
  39. 39.Best estimate of 18 × 56? (a) 1200 (b) 12000 (c) 120
  40. 40.Best estimate of 537 + 752? (a) 1500 (b) 1100 (c) 1300

Answer key

  1. 1700
  2. 2500
  3. 3200
  4. 3600
  5. 3500
  6. 8000
  7. 1300
  8. 800
  9. 500
  10. 4500
  11. 7200
  12. 800
  13. 600
  14. 800
  15. 1000
  16. 2800
  17. 4000
  18. 3000
  19. 2800
  20. 2800
  21. 6300
  22. 6000
  23. 3000
  24. 200
  25. 3200
  26. 2700
  27. 1000
  28. 3000
  29. 900
  30. 800
  31. 1600
  32. 800
  33. 1100
  34. 3600
  35. 6000
  36. 1000
  37. 1000
  38. 800
  39. 1200
  40. 1300

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