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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 751 · 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 497 + 684? (a) 1400 (b) 1000 (c) 1200
  2. 2.Best estimate of 548 + 145? (a) 400 (b) 800 (c) 600
  3. 3.Best estimate of 77 × 22? (a) 1600 (b) 160 (c) 16000
  4. 4.Best estimate of 86 × 36? (a) 360 (b) 3600 (c) 36000
  5. 5.Best estimate of 494 + 186? (a) 700 (b) 900 (c) 500
  6. 6.Best estimate of 243 + 325? (a) 700 (b) 500 (c) 300
  7. 7.Best estimate of 60 × 63? (a) 36000 (b) 3600 (c) 360
  8. 8.Best estimate of 299 + 471? (a) 800 (b) 600 (c) 1000
  9. 9.Best estimate of 27 × 19? (a) 600 (b) 6000 (c) 60
  10. 10.Best estimate of 827 + 856? (a) 1500 (b) 1900 (c) 1700
  11. 11.Best estimate of 30 × 51? (a) 15000 (b) 1500 (c) 150
  12. 12.Best estimate of 31 × 63? (a) 180 (b) 18000 (c) 1800
  13. 13.Best estimate of 56 × 12? (a) 600 (b) 60 (c) 6000
  14. 14.Best estimate of 360 + 303? (a) 900 (b) 500 (c) 700
  15. 15.Best estimate of 488 + 755? (a) 1100 (b) 1500 (c) 1300
  16. 16.Best estimate of 74 × 12? (a) 70 (b) 700 (c) 7000
  17. 17.Best estimate of 82 × 66? (a) 560 (b) 5600 (c) 56000
  18. 18.Best estimate of 720 + 867? (a) 1600 (b) 1400 (c) 1800
  19. 19.Best estimate of 16 × 56? (a) 1200 (b) 120 (c) 12000
  20. 20.Best estimate of 842 + 382? (a) 1200 (b) 1000 (c) 1400
  21. 21.Best estimate of 27 × 63? (a) 1800 (b) 18000 (c) 180
  22. 22.Best estimate of 16 × 66? (a) 140 (b) 1400 (c) 14000
  23. 23.Best estimate of 246 + 212? (a) 400 (b) 600 (c) 200
  24. 24.Best estimate of 56 × 52? (a) 3000 (b) 30000 (c) 300
  25. 25.Best estimate of 42 × 78? (a) 320 (b) 32000 (c) 3200
  26. 26.Best estimate of 678 + 393? (a) 1100 (b) 900 (c) 1300
  27. 27.Best estimate of 59 × 34? (a) 1800 (b) 180 (c) 18000
  28. 28.Best estimate of 120 + 607? (a) 900 (b) 700 (c) 500
  29. 29.Best estimate of 203 + 209? (a) 600 (b) 400 (c) 200
  30. 30.Best estimate of 41 × 36? (a) 16000 (b) 1600 (c) 160
  31. 31.Best estimate of 525 + 837? (a) 1100 (b) 1300 (c) 1500
  32. 32.Best estimate of 60 × 16? (a) 12000 (b) 120 (c) 1200
  33. 33.Best estimate of 51 × 24? (a) 100 (b) 1000 (c) 10000
  34. 34.Best estimate of 321 + 377? (a) 700 (b) 900 (c) 500
  35. 35.Best estimate of 48 × 19? (a) 1000 (b) 100 (c) 10000
  36. 36.Best estimate of 43 × 13? (a) 40 (b) 4000 (c) 400
  37. 37.Best estimate of 79 × 46? (a) 400 (b) 4000 (c) 40000
  38. 38.Best estimate of 21 × 62? (a) 120 (b) 1200 (c) 12000
  39. 39.Best estimate of 677 + 326? (a) 1200 (b) 1000 (c) 800
  40. 40.Best estimate of 40 × 64? (a) 2400 (b) 240 (c) 24000

Answer key

  1. 1200
  2. 600
  3. 1600
  4. 3600
  5. 700
  6. 500
  7. 3600
  8. 800
  9. 600
  10. 1700
  11. 1500
  12. 1800
  13. 600
  14. 700
  15. 1300
  16. 700
  17. 5600
  18. 1600
  19. 1200
  20. 1200
  21. 1800
  22. 1400
  23. 400
  24. 3000
  25. 3200
  26. 1100
  27. 1800
  28. 700
  29. 400
  30. 1600
  31. 1300
  32. 1200
  33. 1000
  34. 700
  35. 1000
  36. 400
  37. 4000
  38. 1200
  39. 1000
  40. 2400

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