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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 912 · 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 22 × 28? (a) 600 (b) 60 (c) 6000
  2. 2.Best estimate of 21 × 88? (a) 18000 (b) 180 (c) 1800
  3. 3.Best estimate of 96 × 30? (a) 3000 (b) 30000 (c) 300
  4. 4.Best estimate of 460 + 747? (a) 1000 (b) 1400 (c) 1200
  5. 5.Best estimate of 140 + 143? (a) 400 (b) 200 (c) 0
  6. 6.Best estimate of 44 × 23? (a) 8000 (b) 80 (c) 800
  7. 7.Best estimate of 37 × 79? (a) 32000 (b) 320 (c) 3200
  8. 8.Best estimate of 47 × 46? (a) 250 (b) 2500 (c) 25000
  9. 9.Best estimate of 62 × 29? (a) 180 (b) 18000 (c) 1800
  10. 10.Best estimate of 37 × 28? (a) 1200 (b) 120 (c) 12000
  11. 11.Best estimate of 805 + 817? (a) 1800 (b) 1400 (c) 1600
  12. 12.Best estimate of 13 × 56? (a) 600 (b) 6000 (c) 60
  13. 13.Best estimate of 29 × 48? (a) 1500 (b) 15000 (c) 150
  14. 14.Best estimate of 58 × 89? (a) 540 (b) 54000 (c) 5400
  15. 15.Best estimate of 867 + 165? (a) 900 (b) 1300 (c) 1100
  16. 16.Best estimate of 326 + 732? (a) 800 (b) 1000 (c) 1200
  17. 17.Best estimate of 318 + 734? (a) 1000 (b) 1200 (c) 800
  18. 18.Best estimate of 66 × 27? (a) 210 (b) 2100 (c) 21000
  19. 19.Best estimate of 96 × 67? (a) 7000 (b) 70000 (c) 700
  20. 20.Best estimate of 52 × 27? (a) 15000 (b) 150 (c) 1500
  21. 21.Best estimate of 519 + 508? (a) 1000 (b) 800 (c) 1200
  22. 22.Best estimate of 771 + 160? (a) 800 (b) 1000 (c) 1200
  23. 23.Best estimate of 19 × 89? (a) 180 (b) 1800 (c) 18000
  24. 24.Best estimate of 598 + 388? (a) 1000 (b) 1200 (c) 800
  25. 25.Best estimate of 276 + 641? (a) 900 (b) 1100 (c) 700
  26. 26.Best estimate of 24 × 57? (a) 1200 (b) 12000 (c) 120
  27. 27.Best estimate of 23 × 48? (a) 100 (b) 1000 (c) 10000
  28. 28.Best estimate of 63 × 40? (a) 240 (b) 2400 (c) 24000
  29. 29.Best estimate of 452 + 198? (a) 700 (b) 900 (c) 500
  30. 30.Best estimate of 39 × 74? (a) 28000 (b) 2800 (c) 280
  31. 31.Best estimate of 577 + 568? (a) 1000 (b) 1200 (c) 1400
  32. 32.Best estimate of 66 × 24? (a) 14000 (b) 1400 (c) 140
  33. 33.Best estimate of 548 + 835? (a) 1500 (b) 1100 (c) 1300
  34. 34.Best estimate of 674 + 574? (a) 1100 (b) 1300 (c) 1500
  35. 35.Best estimate of 745 + 428? (a) 1300 (b) 1100 (c) 900
  36. 36.Best estimate of 22 × 36? (a) 800 (b) 8000 (c) 80
  37. 37.Best estimate of 382 + 182? (a) 800 (b) 400 (c) 600
  38. 38.Best estimate of 96 × 63? (a) 6000 (b) 60000 (c) 600
  39. 39.Best estimate of 730 + 521? (a) 1000 (b) 1400 (c) 1200
  40. 40.Best estimate of 641 + 463? (a) 1300 (b) 900 (c) 1100

Answer key

  1. 600
  2. 1800
  3. 3000
  4. 1200
  5. 200
  6. 800
  7. 3200
  8. 2500
  9. 1800
  10. 1200
  11. 1600
  12. 600
  13. 1500
  14. 5400
  15. 1100
  16. 1000
  17. 1000
  18. 2100
  19. 7000
  20. 1500
  21. 1000
  22. 1000
  23. 1800
  24. 1000
  25. 900
  26. 1200
  27. 1000
  28. 2400
  29. 700
  30. 2800
  31. 1200
  32. 1400
  33. 1300
  34. 1300
  35. 1100
  36. 800
  37. 600
  38. 6000
  39. 1200
  40. 1100

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