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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 783 · 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 490 + 252? (a) 800 (b) 600 (c) 1000
  2. 2.Best estimate of 14 × 61? (a) 60 (b) 600 (c) 6000
  3. 3.Best estimate of 43 × 20? (a) 800 (b) 80 (c) 8000
  4. 4.Best estimate of 29 × 76? (a) 2400 (b) 240 (c) 24000
  5. 5.Best estimate of 40 × 39? (a) 1600 (b) 160 (c) 16000
  6. 6.Best estimate of 58 × 29? (a) 1800 (b) 18000 (c) 180
  7. 7.Best estimate of 94 × 73? (a) 630 (b) 63000 (c) 6300
  8. 8.Best estimate of 743 + 303? (a) 1200 (b) 800 (c) 1000
  9. 9.Best estimate of 819 + 167? (a) 800 (b) 1200 (c) 1000
  10. 10.Best estimate of 435 + 675? (a) 1300 (b) 1100 (c) 900
  11. 11.Best estimate of 34 × 12? (a) 3000 (b) 30 (c) 300
  12. 12.Best estimate of 50 × 73? (a) 3500 (b) 350 (c) 35000
  13. 13.Best estimate of 47 × 30? (a) 15000 (b) 1500 (c) 150
  14. 14.Best estimate of 772 + 143? (a) 900 (b) 700 (c) 1100
  15. 15.Best estimate of 697 + 352? (a) 1100 (b) 1300 (c) 900
  16. 16.Best estimate of 76 × 44? (a) 32000 (b) 3200 (c) 320
  17. 17.Best estimate of 78 × 13? (a) 800 (b) 8000 (c) 80
  18. 18.Best estimate of 12 × 81? (a) 80 (b) 800 (c) 8000
  19. 19.Best estimate of 547 + 226? (a) 700 (b) 500 (c) 900
  20. 20.Best estimate of 567 + 513? (a) 1300 (b) 900 (c) 1100
  21. 21.Best estimate of 76 × 23? (a) 160 (b) 16000 (c) 1600
  22. 22.Best estimate of 537 + 469? (a) 800 (b) 1000 (c) 1200
  23. 23.Best estimate of 532 + 775? (a) 1500 (b) 1300 (c) 1100
  24. 24.Best estimate of 667 + 329? (a) 1200 (b) 800 (c) 1000
  25. 25.Best estimate of 56 × 67? (a) 4200 (b) 420 (c) 42000
  26. 26.Best estimate of 19 × 43? (a) 8000 (b) 800 (c) 80
  27. 27.Best estimate of 26 × 96? (a) 30000 (b) 300 (c) 3000
  28. 28.Best estimate of 30 × 80? (a) 2400 (b) 24000 (c) 240
  29. 29.Best estimate of 72 × 20? (a) 140 (b) 1400 (c) 14000
  30. 30.Best estimate of 498 + 842? (a) 1300 (b) 1500 (c) 1100
  31. 31.Best estimate of 92 × 26? (a) 2700 (b) 27000 (c) 270
  32. 32.Best estimate of 230 + 718? (a) 700 (b) 900 (c) 1100
  33. 33.Best estimate of 51 × 81? (a) 4000 (b) 40000 (c) 400
  34. 34.Best estimate of 821 + 670? (a) 1500 (b) 1300 (c) 1700
  35. 35.Best estimate of 663 + 558? (a) 1500 (b) 1300 (c) 1100
  36. 36.Best estimate of 60 × 92? (a) 540 (b) 54000 (c) 5400
  37. 37.Best estimate of 60 × 71? (a) 4200 (b) 42000 (c) 420
  38. 38.Best estimate of 601 + 169? (a) 600 (b) 800 (c) 1000
  39. 39.Best estimate of 53 × 56? (a) 30000 (b) 3000 (c) 300
  40. 40.Best estimate of 72 × 97? (a) 700 (b) 70000 (c) 7000

Answer key

  1. 800
  2. 600
  3. 800
  4. 2400
  5. 1600
  6. 1800
  7. 6300
  8. 1000
  9. 1000
  10. 1100
  11. 300
  12. 3500
  13. 1500
  14. 900
  15. 1100
  16. 3200
  17. 800
  18. 800
  19. 700
  20. 1100
  21. 1600
  22. 1000
  23. 1300
  24. 1000
  25. 4200
  26. 800
  27. 3000
  28. 2400
  29. 1400
  30. 1300
  31. 2700
  32. 900
  33. 4000
  34. 1500
  35. 1300
  36. 5400
  37. 4200
  38. 800
  39. 3000
  40. 7000

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