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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 569 · 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 79 × 19? (a) 16000 (b) 1600 (c) 160
  2. 2.Best estimate of 14 × 22? (a) 200 (b) 2000 (c) 20
  3. 3.Best estimate of 18 × 44? (a) 8000 (b) 800 (c) 80
  4. 4.Best estimate of 456 + 399? (a) 700 (b) 900 (c) 1100
  5. 5.Best estimate of 89 × 63? (a) 54000 (b) 540 (c) 5400
  6. 6.Best estimate of 314 + 774? (a) 1100 (b) 1300 (c) 900
  7. 7.Best estimate of 89 × 36? (a) 36000 (b) 3600 (c) 360
  8. 8.Best estimate of 71 × 69? (a) 490 (b) 49000 (c) 4900
  9. 9.Best estimate of 29 × 76? (a) 2400 (b) 240 (c) 24000
  10. 10.Best estimate of 507 + 177? (a) 500 (b) 900 (c) 700
  11. 11.Best estimate of 498 + 186? (a) 500 (b) 700 (c) 900
  12. 12.Best estimate of 43 × 68? (a) 2800 (b) 28000 (c) 280
  13. 13.Best estimate of 77 × 20? (a) 16000 (b) 160 (c) 1600
  14. 14.Best estimate of 96 × 36? (a) 400 (b) 40000 (c) 4000
  15. 15.Best estimate of 70 × 87? (a) 6300 (b) 63000 (c) 630
  16. 16.Best estimate of 20 × 22? (a) 40 (b) 4000 (c) 400
  17. 17.Best estimate of 437 + 275? (a) 900 (b) 500 (c) 700
  18. 18.Best estimate of 657 + 852? (a) 1600 (b) 1400 (c) 1800
  19. 19.Best estimate of 70 × 88? (a) 6300 (b) 630 (c) 63000
  20. 20.Best estimate of 880 + 788? (a) 1500 (b) 1700 (c) 1900
  21. 21.Best estimate of 94 × 60? (a) 5400 (b) 54000 (c) 540
  22. 22.Best estimate of 860 + 140? (a) 800 (b) 1200 (c) 1000
  23. 23.Best estimate of 684 + 435? (a) 1300 (b) 1100 (c) 900
  24. 24.Best estimate of 70 × 58? (a) 420 (b) 4200 (c) 42000
  25. 25.Best estimate of 302 + 404? (a) 900 (b) 500 (c) 700
  26. 26.Best estimate of 71 × 67? (a) 49000 (b) 490 (c) 4900
  27. 27.Best estimate of 86 × 70? (a) 6300 (b) 630 (c) 63000
  28. 28.Best estimate of 79 × 14? (a) 80 (b) 8000 (c) 800
  29. 29.Best estimate of 69 × 86? (a) 6300 (b) 630 (c) 63000
  30. 30.Best estimate of 62 × 80? (a) 480 (b) 48000 (c) 4800
  31. 31.Best estimate of 185 + 280? (a) 500 (b) 300 (c) 700
  32. 32.Best estimate of 13 × 29? (a) 300 (b) 3000 (c) 30
  33. 33.Best estimate of 880 + 140? (a) 1000 (b) 800 (c) 1200
  34. 34.Best estimate of 16 × 16? (a) 400 (b) 4000 (c) 40
  35. 35.Best estimate of 254 + 236? (a) 500 (b) 700 (c) 300
  36. 36.Best estimate of 222 + 188? (a) 400 (b) 200 (c) 600
  37. 37.Best estimate of 37 × 54? (a) 2000 (b) 20000 (c) 200
  38. 38.Best estimate of 48 × 66? (a) 35000 (b) 350 (c) 3500
  39. 39.Best estimate of 26 × 80? (a) 240 (b) 24000 (c) 2400
  40. 40.Best estimate of 861 + 343? (a) 1000 (b) 1200 (c) 1400

Answer key

  1. 1600
  2. 200
  3. 800
  4. 900
  5. 5400
  6. 1100
  7. 3600
  8. 4900
  9. 2400
  10. 700
  11. 700
  12. 2800
  13. 1600
  14. 4000
  15. 6300
  16. 400
  17. 700
  18. 1600
  19. 6300
  20. 1700
  21. 5400
  22. 1000
  23. 1100
  24. 4200
  25. 700
  26. 4900
  27. 6300
  28. 800
  29. 6300
  30. 4800
  31. 500
  32. 300
  33. 1000
  34. 400
  35. 500
  36. 400
  37. 2000
  38. 3500
  39. 2400
  40. 1200

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