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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 880 · 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 533 + 843? (a) 1300 (b) 1500 (c) 1100
  2. 2.Best estimate of 71 × 83? (a) 5600 (b) 560 (c) 56000
  3. 3.Best estimate of 707 + 705? (a) 1400 (b) 1600 (c) 1200
  4. 4.Best estimate of 83 × 19? (a) 1600 (b) 16000 (c) 160
  5. 5.Best estimate of 241 + 386? (a) 800 (b) 600 (c) 400
  6. 6.Best estimate of 674 + 574? (a) 1300 (b) 1500 (c) 1100
  7. 7.Best estimate of 28 × 43? (a) 120 (b) 1200 (c) 12000
  8. 8.Best estimate of 271 + 838? (a) 900 (b) 1300 (c) 1100
  9. 9.Best estimate of 330 + 751? (a) 900 (b) 1300 (c) 1100
  10. 10.Best estimate of 39 × 17? (a) 8000 (b) 80 (c) 800
  11. 11.Best estimate of 164 + 267? (a) 500 (b) 700 (c) 300
  12. 12.Best estimate of 81 × 18? (a) 1600 (b) 160 (c) 16000
  13. 13.Best estimate of 402 + 312? (a) 700 (b) 900 (c) 500
  14. 14.Best estimate of 847 + 414? (a) 1200 (b) 1000 (c) 1400
  15. 15.Best estimate of 714 + 498? (a) 1200 (b) 1000 (c) 1400
  16. 16.Best estimate of 19 × 39? (a) 80 (b) 8000 (c) 800
  17. 17.Best estimate of 74 × 27? (a) 21000 (b) 210 (c) 2100
  18. 18.Best estimate of 454 + 146? (a) 400 (b) 600 (c) 800
  19. 19.Best estimate of 30 × 32? (a) 9000 (b) 90 (c) 900
  20. 20.Best estimate of 56 × 31? (a) 18000 (b) 180 (c) 1800
  21. 21.Best estimate of 73 × 80? (a) 56000 (b) 560 (c) 5600
  22. 22.Best estimate of 96 × 24? (a) 200 (b) 2000 (c) 20000
  23. 23.Best estimate of 51 × 77? (a) 4000 (b) 40000 (c) 400
  24. 24.Best estimate of 66 × 28? (a) 21000 (b) 2100 (c) 210
  25. 25.Best estimate of 33 × 67? (a) 2100 (b) 21000 (c) 210
  26. 26.Best estimate of 331 + 243? (a) 300 (b) 700 (c) 500
  27. 27.Best estimate of 592 + 646? (a) 1200 (b) 1000 (c) 1400
  28. 28.Best estimate of 480 + 412? (a) 1100 (b) 700 (c) 900
  29. 29.Best estimate of 148 + 747? (a) 1000 (b) 600 (c) 800
  30. 30.Best estimate of 343 + 735? (a) 1200 (b) 800 (c) 1000
  31. 31.Best estimate of 879 + 326? (a) 1400 (b) 1200 (c) 1000
  32. 32.Best estimate of 88 × 13? (a) 9000 (b) 900 (c) 90
  33. 33.Best estimate of 92 × 84? (a) 7200 (b) 72000 (c) 720
  34. 34.Best estimate of 46 × 94? (a) 45000 (b) 4500 (c) 450
  35. 35.Best estimate of 582 + 558? (a) 1400 (b) 1200 (c) 1000
  36. 36.Best estimate of 826 + 466? (a) 1500 (b) 1300 (c) 1100
  37. 37.Best estimate of 84 × 69? (a) 560 (b) 5600 (c) 56000
  38. 38.Best estimate of 26 × 86? (a) 27000 (b) 270 (c) 2700
  39. 39.Best estimate of 59 × 69? (a) 420 (b) 42000 (c) 4200
  40. 40.Best estimate of 60 × 54? (a) 30000 (b) 3000 (c) 300

Answer key

  1. 1300
  2. 5600
  3. 1400
  4. 1600
  5. 600
  6. 1300
  7. 1200
  8. 1100
  9. 1100
  10. 800
  11. 500
  12. 1600
  13. 700
  14. 1200
  15. 1200
  16. 800
  17. 2100
  18. 600
  19. 900
  20. 1800
  21. 5600
  22. 2000
  23. 4000
  24. 2100
  25. 2100
  26. 500
  27. 1200
  28. 900
  29. 800
  30. 1000
  31. 1200
  32. 900
  33. 7200
  34. 4500
  35. 1200
  36. 1300
  37. 5600
  38. 2700
  39. 4200
  40. 3000

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