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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 844 · 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 779 + 508? (a) 1300 (b) 1100 (c) 1500
  2. 2.Best estimate of 607 + 293? (a) 700 (b) 1100 (c) 900
  3. 3.Best estimate of 641 + 460? (a) 1300 (b) 900 (c) 1100
  4. 4.Best estimate of 608 + 281? (a) 1100 (b) 700 (c) 900
  5. 5.Best estimate of 72 × 43? (a) 280 (b) 2800 (c) 28000
  6. 6.Best estimate of 20 × 19? (a) 4000 (b) 40 (c) 400
  7. 7.Best estimate of 519 + 808? (a) 1300 (b) 1500 (c) 1100
  8. 8.Best estimate of 93 × 70? (a) 6300 (b) 630 (c) 63000
  9. 9.Best estimate of 51 × 72? (a) 35000 (b) 350 (c) 3500
  10. 10.Best estimate of 276 + 719? (a) 800 (b) 1000 (c) 1200
  11. 11.Best estimate of 654 + 870? (a) 1600 (b) 1400 (c) 1800
  12. 12.Best estimate of 178 + 676? (a) 1100 (b) 700 (c) 900
  13. 13.Best estimate of 505 + 130? (a) 400 (b) 600 (c) 800
  14. 14.Best estimate of 40 × 47? (a) 2000 (b) 20000 (c) 200
  15. 15.Best estimate of 203 + 445? (a) 400 (b) 600 (c) 800
  16. 16.Best estimate of 61 × 36? (a) 24000 (b) 240 (c) 2400
  17. 17.Best estimate of 62 × 48? (a) 30000 (b) 3000 (c) 300
  18. 18.Best estimate of 36 × 94? (a) 36000 (b) 360 (c) 3600
  19. 19.Best estimate of 36 × 78? (a) 320 (b) 32000 (c) 3200
  20. 20.Best estimate of 627 + 659? (a) 1500 (b) 1300 (c) 1100
  21. 21.Best estimate of 20 × 84? (a) 16000 (b) 1600 (c) 160
  22. 22.Best estimate of 96 × 32? (a) 30000 (b) 300 (c) 3000
  23. 23.Best estimate of 444 + 858? (a) 1100 (b) 1300 (c) 1500
  24. 24.Best estimate of 551 + 232? (a) 800 (b) 600 (c) 1000
  25. 25.Best estimate of 60 × 91? (a) 54000 (b) 5400 (c) 540
  26. 26.Best estimate of 575 + 481? (a) 1300 (b) 900 (c) 1100
  27. 27.Best estimate of 83 × 86? (a) 7200 (b) 72000 (c) 720
  28. 28.Best estimate of 46 × 98? (a) 500 (b) 50000 (c) 5000
  29. 29.Best estimate of 625 + 753? (a) 1200 (b) 1400 (c) 1600
  30. 30.Best estimate of 17 × 24? (a) 400 (b) 4000 (c) 40
  31. 31.Best estimate of 70 × 78? (a) 5600 (b) 560 (c) 56000
  32. 32.Best estimate of 417 + 700? (a) 1100 (b) 1300 (c) 900
  33. 33.Best estimate of 60 × 79? (a) 4800 (b) 48000 (c) 480
  34. 34.Best estimate of 43 × 32? (a) 1200 (b) 120 (c) 12000
  35. 35.Best estimate of 718 + 819? (a) 1700 (b) 1500 (c) 1300
  36. 36.Best estimate of 548 + 355? (a) 700 (b) 900 (c) 1100
  37. 37.Best estimate of 828 + 220? (a) 800 (b) 1200 (c) 1000
  38. 38.Best estimate of 49 × 18? (a) 1000 (b) 100 (c) 10000
  39. 39.Best estimate of 46 × 70? (a) 3500 (b) 35000 (c) 350
  40. 40.Best estimate of 57 × 93? (a) 54000 (b) 5400 (c) 540

Answer key

  1. 1300
  2. 900
  3. 1100
  4. 900
  5. 2800
  6. 400
  7. 1300
  8. 6300
  9. 3500
  10. 1000
  11. 1600
  12. 900
  13. 600
  14. 2000
  15. 600
  16. 2400
  17. 3000
  18. 3600
  19. 3200
  20. 1300
  21. 1600
  22. 3000
  23. 1300
  24. 800
  25. 5400
  26. 1100
  27. 7200
  28. 5000
  29. 1400
  30. 400
  31. 5600
  32. 1100
  33. 4800
  34. 1200
  35. 1500
  36. 900
  37. 1000
  38. 1000
  39. 3500
  40. 5400

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