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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 767 · 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 414 + 421? (a) 1000 (b) 800 (c) 600
  2. 2.Best estimate of 238 + 876? (a) 1100 (b) 1300 (c) 900
  3. 3.Best estimate of 225 + 577? (a) 600 (b) 1000 (c) 800
  4. 4.Best estimate of 48 × 19? (a) 100 (b) 10000 (c) 1000
  5. 5.Best estimate of 633 + 435? (a) 800 (b) 1000 (c) 1200
  6. 6.Best estimate of 493 + 476? (a) 1000 (b) 800 (c) 1200
  7. 7.Best estimate of 37 × 33? (a) 1200 (b) 12000 (c) 120
  8. 8.Best estimate of 195 + 408? (a) 400 (b) 600 (c) 800
  9. 9.Best estimate of 54 × 69? (a) 35000 (b) 350 (c) 3500
  10. 10.Best estimate of 50 × 57? (a) 3000 (b) 30000 (c) 300
  11. 11.Best estimate of 762 + 771? (a) 1600 (b) 1800 (c) 1400
  12. 12.Best estimate of 694 + 327? (a) 1200 (b) 800 (c) 1000
  13. 13.Best estimate of 191 + 159? (a) 200 (b) 400 (c) 600
  14. 14.Best estimate of 51 × 56? (a) 3000 (b) 30000 (c) 300
  15. 15.Best estimate of 258 + 651? (a) 1200 (b) 800 (c) 1000
  16. 16.Best estimate of 751 + 634? (a) 1400 (b) 1200 (c) 1600
  17. 17.Best estimate of 573 + 607? (a) 1200 (b) 1400 (c) 1000
  18. 18.Best estimate of 30 × 18? (a) 60 (b) 6000 (c) 600
  19. 19.Best estimate of 30 × 82? (a) 24000 (b) 2400 (c) 240
  20. 20.Best estimate of 354 + 178? (a) 600 (b) 400 (c) 800
  21. 21.Best estimate of 189 + 834? (a) 800 (b) 1200 (c) 1000
  22. 22.Best estimate of 26 × 58? (a) 18000 (b) 180 (c) 1800
  23. 23.Best estimate of 73 × 28? (a) 210 (b) 21000 (c) 2100
  24. 24.Best estimate of 322 + 164? (a) 500 (b) 300 (c) 700
  25. 25.Best estimate of 714 + 872? (a) 1400 (b) 1600 (c) 1800
  26. 26.Best estimate of 69 × 97? (a) 700 (b) 70000 (c) 7000
  27. 27.Best estimate of 13 × 78? (a) 8000 (b) 80 (c) 800
  28. 28.Best estimate of 68 × 73? (a) 49000 (b) 4900 (c) 490
  29. 29.Best estimate of 382 + 134? (a) 300 (b) 500 (c) 700
  30. 30.Best estimate of 649 + 195? (a) 1000 (b) 800 (c) 600
  31. 31.Best estimate of 371 + 788? (a) 1400 (b) 1200 (c) 1000
  32. 32.Best estimate of 156 + 181? (a) 200 (b) 600 (c) 400
  33. 33.Best estimate of 26 × 57? (a) 1800 (b) 180 (c) 18000
  34. 34.Best estimate of 82 × 48? (a) 4000 (b) 40000 (c) 400
  35. 35.Best estimate of 253 + 601? (a) 700 (b) 1100 (c) 900
  36. 36.Best estimate of 508 + 438? (a) 700 (b) 900 (c) 1100
  37. 37.Best estimate of 288 + 716? (a) 1200 (b) 1000 (c) 800
  38. 38.Best estimate of 391 + 871? (a) 1500 (b) 1100 (c) 1300
  39. 39.Best estimate of 272 + 520? (a) 1000 (b) 600 (c) 800
  40. 40.Best estimate of 78 × 60? (a) 4800 (b) 48000 (c) 480

Answer key

  1. 800
  2. 1100
  3. 800
  4. 1000
  5. 1000
  6. 1000
  7. 1200
  8. 600
  9. 3500
  10. 3000
  11. 1600
  12. 1000
  13. 400
  14. 3000
  15. 1000
  16. 1400
  17. 1200
  18. 600
  19. 2400
  20. 600
  21. 1000
  22. 1800
  23. 2100
  24. 500
  25. 1600
  26. 7000
  27. 800
  28. 4900
  29. 500
  30. 800
  31. 1200
  32. 400
  33. 1800
  34. 4000
  35. 900
  36. 900
  37. 1000
  38. 1300
  39. 800
  40. 4800

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