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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 790 · 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 36 × 72? (a) 28000 (b) 280 (c) 2800
  2. 2.Best estimate of 291 + 382? (a) 700 (b) 900 (c) 500
  3. 3.Best estimate of 43 × 50? (a) 2000 (b) 20000 (c) 200
  4. 4.Best estimate of 876 + 294? (a) 1200 (b) 1400 (c) 1000
  5. 5.Best estimate of 273 + 442? (a) 700 (b) 500 (c) 900
  6. 6.Best estimate of 53 × 77? (a) 400 (b) 40000 (c) 4000
  7. 7.Best estimate of 526 + 196? (a) 700 (b) 900 (c) 500
  8. 8.Best estimate of 248 + 139? (a) 100 (b) 300 (c) 500
  9. 9.Best estimate of 52 × 87? (a) 450 (b) 4500 (c) 45000
  10. 10.Best estimate of 36 × 42? (a) 160 (b) 16000 (c) 1600
  11. 11.Best estimate of 456 + 310? (a) 600 (b) 1000 (c) 800
  12. 12.Best estimate of 672 + 498? (a) 1200 (b) 1000 (c) 1400
  13. 13.Best estimate of 417 + 402? (a) 600 (b) 1000 (c) 800
  14. 14.Best estimate of 66 × 34? (a) 2100 (b) 21000 (c) 210
  15. 15.Best estimate of 52 × 21? (a) 100 (b) 10000 (c) 1000
  16. 16.Best estimate of 659 + 766? (a) 1700 (b) 1500 (c) 1300
  17. 17.Best estimate of 30 × 70? (a) 21000 (b) 210 (c) 2100
  18. 18.Best estimate of 26 × 66? (a) 21000 (b) 2100 (c) 210
  19. 19.Best estimate of 42 × 86? (a) 360 (b) 3600 (c) 36000
  20. 20.Best estimate of 692 + 207? (a) 900 (b) 1100 (c) 700
  21. 21.Best estimate of 86 × 59? (a) 540 (b) 54000 (c) 5400
  22. 22.Best estimate of 36 × 32? (a) 1200 (b) 12000 (c) 120
  23. 23.Best estimate of 293 + 615? (a) 700 (b) 1100 (c) 900
  24. 24.Best estimate of 19 × 64? (a) 120 (b) 12000 (c) 1200
  25. 25.Best estimate of 378 + 491? (a) 900 (b) 1100 (c) 700
  26. 26.Best estimate of 13 × 21? (a) 2000 (b) 20 (c) 200
  27. 27.Best estimate of 811 + 243? (a) 1000 (b) 1200 (c) 800
  28. 28.Best estimate of 144 + 434? (a) 500 (b) 300 (c) 700
  29. 29.Best estimate of 69 × 53? (a) 35000 (b) 3500 (c) 350
  30. 30.Best estimate of 16 × 46? (a) 10000 (b) 1000 (c) 100
  31. 31.Best estimate of 37 × 77? (a) 320 (b) 3200 (c) 32000
  32. 32.Best estimate of 47 × 96? (a) 50000 (b) 500 (c) 5000
  33. 33.Best estimate of 54 × 76? (a) 40000 (b) 400 (c) 4000
  34. 34.Best estimate of 19 × 42? (a) 800 (b) 80 (c) 8000
  35. 35.Best estimate of 370 + 214? (a) 600 (b) 400 (c) 800
  36. 36.Best estimate of 207 + 344? (a) 700 (b) 300 (c) 500
  37. 37.Best estimate of 96 × 34? (a) 300 (b) 3000 (c) 30000
  38. 38.Best estimate of 36 × 27? (a) 1200 (b) 120 (c) 12000
  39. 39.Best estimate of 60 × 84? (a) 480 (b) 48000 (c) 4800
  40. 40.Best estimate of 770 + 244? (a) 1000 (b) 1200 (c) 800

Answer key

  1. 2800
  2. 700
  3. 2000
  4. 1200
  5. 700
  6. 4000
  7. 700
  8. 300
  9. 4500
  10. 1600
  11. 800
  12. 1200
  13. 800
  14. 2100
  15. 1000
  16. 1500
  17. 2100
  18. 2100
  19. 3600
  20. 900
  21. 5400
  22. 1200
  23. 900
  24. 1200
  25. 900
  26. 200
  27. 1000
  28. 500
  29. 3500
  30. 1000
  31. 3200
  32. 5000
  33. 4000
  34. 800
  35. 600
  36. 500
  37. 3000
  38. 1200
  39. 4800
  40. 1000

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