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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 531 · 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 314 + 297? (a) 800 (b) 600 (c) 400
  2. 2.Best estimate of 290 + 856? (a) 1400 (b) 1200 (c) 1000
  3. 3.Best estimate of 23 × 84? (a) 16000 (b) 160 (c) 1600
  4. 4.Best estimate of 270 + 544? (a) 1000 (b) 800 (c) 600
  5. 5.Best estimate of 42 × 33? (a) 12000 (b) 120 (c) 1200
  6. 6.Best estimate of 44 × 62? (a) 240 (b) 2400 (c) 24000
  7. 7.Best estimate of 58 × 52? (a) 300 (b) 3000 (c) 30000
  8. 8.Best estimate of 480 + 129? (a) 800 (b) 400 (c) 600
  9. 9.Best estimate of 22 × 27? (a) 600 (b) 60 (c) 6000
  10. 10.Best estimate of 29 × 46? (a) 150 (b) 15000 (c) 1500
  11. 11.Best estimate of 163 + 759? (a) 800 (b) 1200 (c) 1000
  12. 12.Best estimate of 18 × 38? (a) 80 (b) 8000 (c) 800
  13. 13.Best estimate of 74 × 19? (a) 14000 (b) 1400 (c) 140
  14. 14.Best estimate of 77 × 12? (a) 80 (b) 800 (c) 8000
  15. 15.Best estimate of 147 + 471? (a) 600 (b) 800 (c) 400
  16. 16.Best estimate of 50 × 13? (a) 500 (b) 5000 (c) 50
  17. 17.Best estimate of 290 + 449? (a) 700 (b) 900 (c) 500
  18. 18.Best estimate of 147 + 361? (a) 500 (b) 300 (c) 700
  19. 19.Best estimate of 34 × 83? (a) 2400 (b) 24000 (c) 240
  20. 20.Best estimate of 22 × 67? (a) 140 (b) 14000 (c) 1400
  21. 21.Best estimate of 408 + 755? (a) 1400 (b) 1000 (c) 1200
  22. 22.Best estimate of 258 + 145? (a) 600 (b) 200 (c) 400
  23. 23.Best estimate of 231 + 276? (a) 500 (b) 300 (c) 700
  24. 24.Best estimate of 61 × 26? (a) 18000 (b) 1800 (c) 180
  25. 25.Best estimate of 29 × 87? (a) 27000 (b) 2700 (c) 270
  26. 26.Best estimate of 20 × 69? (a) 140 (b) 14000 (c) 1400
  27. 27.Best estimate of 31 × 50? (a) 1500 (b) 15000 (c) 150
  28. 28.Best estimate of 377 + 167? (a) 400 (b) 600 (c) 800
  29. 29.Best estimate of 482 + 301? (a) 1000 (b) 600 (c) 800
  30. 30.Best estimate of 38 × 64? (a) 24000 (b) 2400 (c) 240
  31. 31.Best estimate of 26 × 59? (a) 1800 (b) 180 (c) 18000
  32. 32.Best estimate of 206 + 849? (a) 1000 (b) 1200 (c) 800
  33. 33.Best estimate of 91 × 72? (a) 63000 (b) 6300 (c) 630
  34. 34.Best estimate of 594 + 682? (a) 1100 (b) 1300 (c) 1500
  35. 35.Best estimate of 676 + 606? (a) 1500 (b) 1100 (c) 1300
  36. 36.Best estimate of 54 × 26? (a) 150 (b) 15000 (c) 1500
  37. 37.Best estimate of 721 + 426? (a) 1300 (b) 1100 (c) 900
  38. 38.Best estimate of 524 + 239? (a) 900 (b) 500 (c) 700
  39. 39.Best estimate of 709 + 236? (a) 700 (b) 900 (c) 1100
  40. 40.Best estimate of 39 × 57? (a) 2400 (b) 240 (c) 24000

Answer key

  1. 600
  2. 1200
  3. 1600
  4. 800
  5. 1200
  6. 2400
  7. 3000
  8. 600
  9. 600
  10. 1500
  11. 1000
  12. 800
  13. 1400
  14. 800
  15. 600
  16. 500
  17. 700
  18. 500
  19. 2400
  20. 1400
  21. 1200
  22. 400
  23. 500
  24. 1800
  25. 2700
  26. 1400
  27. 1500
  28. 600
  29. 800
  30. 2400
  31. 1800
  32. 1000
  33. 6300
  34. 1300
  35. 1300
  36. 1500
  37. 1100
  38. 700
  39. 900
  40. 2400

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