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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 656 · 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 14 × 13? (a) 100 (b) 10 (c) 1000
  2. 2.Best estimate of 89 × 97? (a) 90000 (b) 900 (c) 9000
  3. 3.Best estimate of 17 × 26? (a) 600 (b) 6000 (c) 60
  4. 4.Best estimate of 79 × 59? (a) 48000 (b) 4800 (c) 480
  5. 5.Best estimate of 129 + 840? (a) 700 (b) 1100 (c) 900
  6. 6.Best estimate of 878 + 706? (a) 1400 (b) 1600 (c) 1800
  7. 7.Best estimate of 723 + 727? (a) 1200 (b) 1600 (c) 1400
  8. 8.Best estimate of 519 + 151? (a) 900 (b) 500 (c) 700
  9. 9.Best estimate of 84 × 34? (a) 240 (b) 24000 (c) 2400
  10. 10.Best estimate of 273 + 324? (a) 400 (b) 800 (c) 600
  11. 11.Best estimate of 571 + 444? (a) 1000 (b) 1200 (c) 800
  12. 12.Best estimate of 257 + 134? (a) 600 (b) 200 (c) 400
  13. 13.Best estimate of 89 × 61? (a) 54000 (b) 540 (c) 5400
  14. 14.Best estimate of 713 + 240? (a) 700 (b) 900 (c) 1100
  15. 15.Best estimate of 71 × 46? (a) 3500 (b) 35000 (c) 350
  16. 16.Best estimate of 46 × 94? (a) 4500 (b) 450 (c) 45000
  17. 17.Best estimate of 200 + 410? (a) 800 (b) 600 (c) 400
  18. 18.Best estimate of 139 + 244? (a) 500 (b) 300 (c) 100
  19. 19.Best estimate of 96 × 23? (a) 20000 (b) 200 (c) 2000
  20. 20.Best estimate of 16 × 16? (a) 4000 (b) 400 (c) 40
  21. 21.Best estimate of 16 × 73? (a) 1400 (b) 14000 (c) 140
  22. 22.Best estimate of 52 × 43? (a) 200 (b) 20000 (c) 2000
  23. 23.Best estimate of 71 × 17? (a) 1400 (b) 140 (c) 14000
  24. 24.Best estimate of 73 × 98? (a) 7000 (b) 70000 (c) 700
  25. 25.Best estimate of 36 × 63? (a) 2400 (b) 24000 (c) 240
  26. 26.Best estimate of 14 × 81? (a) 8000 (b) 80 (c) 800
  27. 27.Best estimate of 32 × 24? (a) 6000 (b) 600 (c) 60
  28. 28.Best estimate of 37 × 23? (a) 800 (b) 8000 (c) 80
  29. 29.Best estimate of 47 × 81? (a) 4000 (b) 40000 (c) 400
  30. 30.Best estimate of 32 × 31? (a) 90 (b) 900 (c) 9000
  31. 31.Best estimate of 81 × 81? (a) 64000 (b) 6400 (c) 640
  32. 32.Best estimate of 330 + 204? (a) 700 (b) 300 (c) 500
  33. 33.Best estimate of 20 × 32? (a) 6000 (b) 60 (c) 600
  34. 34.Best estimate of 208 + 682? (a) 700 (b) 900 (c) 1100
  35. 35.Best estimate of 92 × 32? (a) 2700 (b) 27000 (c) 270
  36. 36.Best estimate of 73 × 30? (a) 210 (b) 2100 (c) 21000
  37. 37.Best estimate of 27 × 91? (a) 27000 (b) 270 (c) 2700
  38. 38.Best estimate of 825 + 638? (a) 1200 (b) 1600 (c) 1400
  39. 39.Best estimate of 222 + 843? (a) 800 (b) 1200 (c) 1000
  40. 40.Best estimate of 48 × 93? (a) 450 (b) 45000 (c) 4500

Answer key

  1. 100
  2. 9000
  3. 600
  4. 4800
  5. 900
  6. 1600
  7. 1400
  8. 700
  9. 2400
  10. 600
  11. 1000
  12. 400
  13. 5400
  14. 900
  15. 3500
  16. 4500
  17. 600
  18. 300
  19. 2000
  20. 400
  21. 1400
  22. 2000
  23. 1400
  24. 7000
  25. 2400
  26. 800
  27. 600
  28. 800
  29. 4000
  30. 900
  31. 6400
  32. 500
  33. 600
  34. 900
  35. 2700
  36. 2100
  37. 2700
  38. 1400
  39. 1000
  40. 4500

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