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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 908 · 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 38 × 82? (a) 3200 (b) 32000 (c) 320
  2. 2.Best estimate of 252 + 380? (a) 900 (b) 500 (c) 700
  3. 3.Best estimate of 157 + 620? (a) 800 (b) 1000 (c) 600
  4. 4.Best estimate of 86 × 28? (a) 270 (b) 2700 (c) 27000
  5. 5.Best estimate of 854 + 687? (a) 1800 (b) 1400 (c) 1600
  6. 6.Best estimate of 201 + 707? (a) 1100 (b) 900 (c) 700
  7. 7.Best estimate of 47 × 14? (a) 5000 (b) 50 (c) 500
  8. 8.Best estimate of 842 + 304? (a) 1300 (b) 1100 (c) 900
  9. 9.Best estimate of 70 × 53? (a) 350 (b) 3500 (c) 35000
  10. 10.Best estimate of 13 × 67? (a) 700 (b) 7000 (c) 70
  11. 11.Best estimate of 29 × 86? (a) 2700 (b) 27000 (c) 270
  12. 12.Best estimate of 677 + 843? (a) 1500 (b) 1300 (c) 1700
  13. 13.Best estimate of 713 + 255? (a) 1200 (b) 1000 (c) 800
  14. 14.Best estimate of 242 + 467? (a) 700 (b) 500 (c) 900
  15. 15.Best estimate of 18 × 79? (a) 1600 (b) 16000 (c) 160
  16. 16.Best estimate of 315 + 646? (a) 700 (b) 900 (c) 1100
  17. 17.Best estimate of 41 × 33? (a) 120 (b) 1200 (c) 12000
  18. 18.Best estimate of 67 × 46? (a) 350 (b) 3500 (c) 35000
  19. 19.Best estimate of 51 × 86? (a) 450 (b) 45000 (c) 4500
  20. 20.Best estimate of 80 × 16? (a) 160 (b) 1600 (c) 16000
  21. 21.Best estimate of 76 × 76? (a) 640 (b) 6400 (c) 64000
  22. 22.Best estimate of 425 + 729? (a) 900 (b) 1300 (c) 1100
  23. 23.Best estimate of 189 + 609? (a) 800 (b) 1000 (c) 600
  24. 24.Best estimate of 38 × 46? (a) 2000 (b) 200 (c) 20000
  25. 25.Best estimate of 625 + 653? (a) 1500 (b) 1300 (c) 1100
  26. 26.Best estimate of 86 × 56? (a) 54000 (b) 5400 (c) 540
  27. 27.Best estimate of 96 × 54? (a) 50000 (b) 5000 (c) 500
  28. 28.Best estimate of 86 × 61? (a) 540 (b) 54000 (c) 5400
  29. 29.Best estimate of 12 × 93? (a) 9000 (b) 90 (c) 900
  30. 30.Best estimate of 607 + 680? (a) 1300 (b) 1100 (c) 1500
  31. 31.Best estimate of 375 + 634? (a) 1000 (b) 800 (c) 1200
  32. 32.Best estimate of 273 + 256? (a) 600 (b) 800 (c) 400
  33. 33.Best estimate of 17 × 92? (a) 1800 (b) 18000 (c) 180
  34. 34.Best estimate of 502 + 602? (a) 900 (b) 1300 (c) 1100
  35. 35.Best estimate of 56 × 81? (a) 48000 (b) 4800 (c) 480
  36. 36.Best estimate of 576 + 227? (a) 600 (b) 800 (c) 1000
  37. 37.Best estimate of 12 × 47? (a) 50 (b) 500 (c) 5000
  38. 38.Best estimate of 659 + 233? (a) 1100 (b) 900 (c) 700
  39. 39.Best estimate of 488 + 605? (a) 1300 (b) 900 (c) 1100
  40. 40.Best estimate of 96 × 73? (a) 7000 (b) 700 (c) 70000

Answer key

  1. 3200
  2. 700
  3. 800
  4. 2700
  5. 1600
  6. 900
  7. 500
  8. 1100
  9. 3500
  10. 700
  11. 2700
  12. 1500
  13. 1000
  14. 700
  15. 1600
  16. 900
  17. 1200
  18. 3500
  19. 4500
  20. 1600
  21. 6400
  22. 1100
  23. 800
  24. 2000
  25. 1300
  26. 5400
  27. 5000
  28. 5400
  29. 900
  30. 1300
  31. 1000
  32. 600
  33. 1800
  34. 1100
  35. 4800
  36. 800
  37. 500
  38. 900
  39. 1100
  40. 7000

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