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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 302 · 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 86 × 59? (a) 54000 (b) 540 (c) 5400
  2. 2.Best estimate of 362 + 469? (a) 700 (b) 1100 (c) 900
  3. 3.Best estimate of 38 × 77? (a) 32000 (b) 320 (c) 3200
  4. 4.Best estimate of 545 + 301? (a) 800 (b) 1000 (c) 600
  5. 5.Best estimate of 76 × 50? (a) 4000 (b) 40000 (c) 400
  6. 6.Best estimate of 545 + 738? (a) 1200 (b) 1400 (c) 1000
  7. 7.Best estimate of 589 + 796? (a) 1200 (b) 1600 (c) 1400
  8. 8.Best estimate of 719 + 313? (a) 800 (b) 1000 (c) 1200
  9. 9.Best estimate of 69 × 16? (a) 14000 (b) 140 (c) 1400
  10. 10.Best estimate of 780 + 342? (a) 1100 (b) 900 (c) 1300
  11. 11.Best estimate of 66 × 52? (a) 3500 (b) 35000 (c) 350
  12. 12.Best estimate of 854 + 202? (a) 900 (b) 1100 (c) 1300
  13. 13.Best estimate of 94 × 50? (a) 45000 (b) 4500 (c) 450
  14. 14.Best estimate of 77 × 94? (a) 72000 (b) 720 (c) 7200
  15. 15.Best estimate of 132 + 710? (a) 600 (b) 1000 (c) 800
  16. 16.Best estimate of 788 + 713? (a) 1700 (b) 1300 (c) 1500
  17. 17.Best estimate of 844 + 352? (a) 1400 (b) 1200 (c) 1000
  18. 18.Best estimate of 27 × 74? (a) 210 (b) 21000 (c) 2100
  19. 19.Best estimate of 77 × 54? (a) 40000 (b) 4000 (c) 400
  20. 20.Best estimate of 228 + 290? (a) 300 (b) 700 (c) 500
  21. 21.Best estimate of 500 + 875? (a) 1200 (b) 1600 (c) 1400
  22. 22.Best estimate of 70 × 23? (a) 1400 (b) 140 (c) 14000
  23. 23.Best estimate of 50 × 47? (a) 25000 (b) 250 (c) 2500
  24. 24.Best estimate of 279 + 478? (a) 600 (b) 1000 (c) 800
  25. 25.Best estimate of 98 × 50? (a) 50000 (b) 500 (c) 5000
  26. 26.Best estimate of 13 × 56? (a) 6000 (b) 60 (c) 600
  27. 27.Best estimate of 54 × 81? (a) 400 (b) 40000 (c) 4000
  28. 28.Best estimate of 593 + 724? (a) 1300 (b) 1100 (c) 1500
  29. 29.Best estimate of 29 × 18? (a) 6000 (b) 60 (c) 600
  30. 30.Best estimate of 710 + 683? (a) 1600 (b) 1200 (c) 1400
  31. 31.Best estimate of 83 × 89? (a) 720 (b) 72000 (c) 7200
  32. 32.Best estimate of 373 + 416? (a) 1000 (b) 800 (c) 600
  33. 33.Best estimate of 18 × 89? (a) 1800 (b) 180 (c) 18000
  34. 34.Best estimate of 427 + 566? (a) 1200 (b) 800 (c) 1000
  35. 35.Best estimate of 364 + 451? (a) 900 (b) 1100 (c) 700
  36. 36.Best estimate of 87 × 92? (a) 8100 (b) 810 (c) 81000
  37. 37.Best estimate of 36 × 74? (a) 2800 (b) 28000 (c) 280
  38. 38.Best estimate of 16 × 86? (a) 18000 (b) 180 (c) 1800
  39. 39.Best estimate of 13 × 70? (a) 70 (b) 7000 (c) 700
  40. 40.Best estimate of 72 × 73? (a) 49000 (b) 490 (c) 4900

Answer key

  1. 5400
  2. 900
  3. 3200
  4. 800
  5. 4000
  6. 1200
  7. 1400
  8. 1000
  9. 1400
  10. 1100
  11. 3500
  12. 1100
  13. 4500
  14. 7200
  15. 800
  16. 1500
  17. 1200
  18. 2100
  19. 4000
  20. 500
  21. 1400
  22. 1400
  23. 2500
  24. 800
  25. 5000
  26. 600
  27. 4000
  28. 1300
  29. 600
  30. 1400
  31. 7200
  32. 800
  33. 1800
  34. 1000
  35. 900
  36. 8100
  37. 2800
  38. 1800
  39. 700
  40. 4900

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