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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 445 · 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 92 × 26? (a) 27000 (b) 2700 (c) 270
  2. 2.Best estimate of 341 + 337? (a) 400 (b) 800 (c) 600
  3. 3.Best estimate of 21 × 64? (a) 12000 (b) 1200 (c) 120
  4. 4.Best estimate of 28 × 63? (a) 1800 (b) 180 (c) 18000
  5. 5.Best estimate of 715 + 186? (a) 1100 (b) 900 (c) 700
  6. 6.Best estimate of 597 + 768? (a) 1600 (b) 1400 (c) 1200
  7. 7.Best estimate of 67 × 16? (a) 1400 (b) 14000 (c) 140
  8. 8.Best estimate of 47 × 80? (a) 4000 (b) 40000 (c) 400
  9. 9.Best estimate of 704 + 465? (a) 1400 (b) 1200 (c) 1000
  10. 10.Best estimate of 50 × 16? (a) 100 (b) 1000 (c) 10000
  11. 11.Best estimate of 52 × 57? (a) 3000 (b) 300 (c) 30000
  12. 12.Best estimate of 145 + 653? (a) 600 (b) 1000 (c) 800
  13. 13.Best estimate of 855 + 341? (a) 1400 (b) 1200 (c) 1000
  14. 14.Best estimate of 16 × 84? (a) 160 (b) 16000 (c) 1600
  15. 15.Best estimate of 62 × 39? (a) 24000 (b) 2400 (c) 240
  16. 16.Best estimate of 644 + 705? (a) 1300 (b) 1500 (c) 1100
  17. 17.Best estimate of 60 × 12? (a) 60 (b) 600 (c) 6000
  18. 18.Best estimate of 84 × 33? (a) 2400 (b) 240 (c) 24000
  19. 19.Best estimate of 46 × 19? (a) 1000 (b) 10000 (c) 100
  20. 20.Best estimate of 81 × 60? (a) 480 (b) 48000 (c) 4800
  21. 21.Best estimate of 73 × 12? (a) 7000 (b) 70 (c) 700
  22. 22.Best estimate of 270 + 198? (a) 700 (b) 500 (c) 300
  23. 23.Best estimate of 16 × 19? (a) 400 (b) 4000 (c) 40
  24. 24.Best estimate of 297 + 751? (a) 1100 (b) 1300 (c) 900
  25. 25.Best estimate of 695 + 489? (a) 1000 (b) 1400 (c) 1200
  26. 26.Best estimate of 422 + 583? (a) 1000 (b) 800 (c) 1200
  27. 27.Best estimate of 27 × 26? (a) 900 (b) 90 (c) 9000
  28. 28.Best estimate of 29 × 34? (a) 90 (b) 900 (c) 9000
  29. 29.Best estimate of 68 × 60? (a) 420 (b) 42000 (c) 4200
  30. 30.Best estimate of 791 + 299? (a) 900 (b) 1100 (c) 1300
  31. 31.Best estimate of 68 × 32? (a) 2100 (b) 21000 (c) 210
  32. 32.Best estimate of 68 × 34? (a) 210 (b) 2100 (c) 21000
  33. 33.Best estimate of 26 × 70? (a) 2100 (b) 21000 (c) 210
  34. 34.Best estimate of 722 + 158? (a) 700 (b) 1100 (c) 900
  35. 35.Best estimate of 249 + 375? (a) 400 (b) 800 (c) 600
  36. 36.Best estimate of 64 × 74? (a) 4200 (b) 42000 (c) 420
  37. 37.Best estimate of 79 × 56? (a) 48000 (b) 480 (c) 4800
  38. 38.Best estimate of 44 × 38? (a) 160 (b) 16000 (c) 1600
  39. 39.Best estimate of 539 + 574? (a) 1300 (b) 900 (c) 1100
  40. 40.Best estimate of 96 × 48? (a) 5000 (b) 50000 (c) 500

Answer key

  1. 2700
  2. 600
  3. 1200
  4. 1800
  5. 900
  6. 1400
  7. 1400
  8. 4000
  9. 1200
  10. 1000
  11. 3000
  12. 800
  13. 1200
  14. 1600
  15. 2400
  16. 1300
  17. 600
  18. 2400
  19. 1000
  20. 4800
  21. 700
  22. 500
  23. 400
  24. 1100
  25. 1200
  26. 1000
  27. 900
  28. 900
  29. 4200
  30. 1100
  31. 2100
  32. 2100
  33. 2100
  34. 900
  35. 600
  36. 4200
  37. 4800
  38. 1600
  39. 1100
  40. 5000

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