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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 893 · 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 380 + 864? (a) 1500 (b) 1300 (c) 1100
  2. 2.Best estimate of 16 × 27? (a) 6000 (b) 60 (c) 600
  3. 3.Best estimate of 466 + 304? (a) 600 (b) 800 (c) 1000
  4. 4.Best estimate of 76 × 62? (a) 480 (b) 48000 (c) 4800
  5. 5.Best estimate of 28 × 26? (a) 9000 (b) 90 (c) 900
  6. 6.Best estimate of 88 × 98? (a) 9000 (b) 90000 (c) 900
  7. 7.Best estimate of 265 + 444? (a) 500 (b) 700 (c) 900
  8. 8.Best estimate of 69 × 12? (a) 700 (b) 7000 (c) 70
  9. 9.Best estimate of 91 × 60? (a) 540 (b) 54000 (c) 5400
  10. 10.Best estimate of 197 + 860? (a) 1100 (b) 900 (c) 1300
  11. 11.Best estimate of 857 + 391? (a) 1500 (b) 1100 (c) 1300
  12. 12.Best estimate of 16 × 81? (a) 160 (b) 1600 (c) 16000
  13. 13.Best estimate of 751 + 193? (a) 1000 (b) 1200 (c) 800
  14. 14.Best estimate of 46 × 36? (a) 2000 (b) 20000 (c) 200
  15. 15.Best estimate of 36 × 33? (a) 1200 (b) 120 (c) 12000
  16. 16.Best estimate of 29 × 66? (a) 2100 (b) 210 (c) 21000
  17. 17.Best estimate of 577 + 209? (a) 800 (b) 1000 (c) 600
  18. 18.Best estimate of 553 + 134? (a) 700 (b) 500 (c) 900
  19. 19.Best estimate of 63 × 66? (a) 42000 (b) 4200 (c) 420
  20. 20.Best estimate of 13 × 76? (a) 800 (b) 8000 (c) 80
  21. 21.Best estimate of 56 × 66? (a) 4200 (b) 420 (c) 42000
  22. 22.Best estimate of 80 × 26? (a) 2400 (b) 24000 (c) 240
  23. 23.Best estimate of 727 + 449? (a) 900 (b) 1300 (c) 1100
  24. 24.Best estimate of 67 × 96? (a) 700 (b) 70000 (c) 7000
  25. 25.Best estimate of 378 + 849? (a) 1000 (b) 1200 (c) 1400
  26. 26.Best estimate of 67 × 57? (a) 42000 (b) 4200 (c) 420
  27. 27.Best estimate of 44 × 84? (a) 3200 (b) 32000 (c) 320
  28. 28.Best estimate of 28 × 90? (a) 27000 (b) 2700 (c) 270
  29. 29.Best estimate of 653 + 822? (a) 1500 (b) 1700 (c) 1300
  30. 30.Best estimate of 51 × 24? (a) 10000 (b) 100 (c) 1000
  31. 31.Best estimate of 856 + 285? (a) 1000 (b) 1400 (c) 1200
  32. 32.Best estimate of 60 × 30? (a) 18000 (b) 180 (c) 1800
  33. 33.Best estimate of 795 + 408? (a) 1400 (b) 1200 (c) 1000
  34. 34.Best estimate of 69 × 29? (a) 21000 (b) 2100 (c) 210
  35. 35.Best estimate of 352 + 198? (a) 600 (b) 800 (c) 400
  36. 36.Best estimate of 347 + 259? (a) 800 (b) 400 (c) 600
  37. 37.Best estimate of 791 + 761? (a) 1600 (b) 1400 (c) 1800
  38. 38.Best estimate of 96 × 19? (a) 20000 (b) 200 (c) 2000
  39. 39.Best estimate of 458 + 254? (a) 800 (b) 600 (c) 1000
  40. 40.Best estimate of 710 + 557? (a) 1500 (b) 1300 (c) 1100

Answer key

  1. 1300
  2. 600
  3. 800
  4. 4800
  5. 900
  6. 9000
  7. 700
  8. 700
  9. 5400
  10. 1100
  11. 1300
  12. 1600
  13. 1000
  14. 2000
  15. 1200
  16. 2100
  17. 800
  18. 700
  19. 4200
  20. 800
  21. 4200
  22. 2400
  23. 1100
  24. 7000
  25. 1200
  26. 4200
  27. 3200
  28. 2700
  29. 1500
  30. 1000
  31. 1200
  32. 1800
  33. 1200
  34. 2100
  35. 600
  36. 600
  37. 1600
  38. 2000
  39. 800
  40. 1300

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