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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 374 · 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 27 × 82? (a) 240 (b) 2400 (c) 24000
  2. 2.Best estimate of 48 × 54? (a) 250 (b) 2500 (c) 25000
  3. 3.Best estimate of 463 + 212? (a) 700 (b) 500 (c) 900
  4. 4.Best estimate of 360 + 636? (a) 800 (b) 1200 (c) 1000
  5. 5.Best estimate of 39 × 59? (a) 24000 (b) 240 (c) 2400
  6. 6.Best estimate of 37 × 59? (a) 2400 (b) 240 (c) 24000
  7. 7.Best estimate of 357 + 495? (a) 900 (b) 1100 (c) 700
  8. 8.Best estimate of 660 + 293? (a) 800 (b) 1000 (c) 1200
  9. 9.Best estimate of 43 × 14? (a) 40 (b) 400 (c) 4000
  10. 10.Best estimate of 16 × 31? (a) 60 (b) 6000 (c) 600
  11. 11.Best estimate of 863 + 228? (a) 900 (b) 1300 (c) 1100
  12. 12.Best estimate of 333 + 267? (a) 600 (b) 400 (c) 800
  13. 13.Best estimate of 36 × 51? (a) 20000 (b) 2000 (c) 200
  14. 14.Best estimate of 78 × 16? (a) 160 (b) 16000 (c) 1600
  15. 15.Best estimate of 684 + 745? (a) 1400 (b) 1600 (c) 1200
  16. 16.Best estimate of 773 + 597? (a) 1400 (b) 1600 (c) 1200
  17. 17.Best estimate of 754 + 788? (a) 1600 (b) 1400 (c) 1800
  18. 18.Best estimate of 30 × 47? (a) 150 (b) 15000 (c) 1500
  19. 19.Best estimate of 384 + 347? (a) 900 (b) 700 (c) 500
  20. 20.Best estimate of 481 + 221? (a) 500 (b) 900 (c) 700
  21. 21.Best estimate of 136 + 565? (a) 900 (b) 500 (c) 700
  22. 22.Best estimate of 74 × 48? (a) 35000 (b) 3500 (c) 350
  23. 23.Best estimate of 46 × 81? (a) 400 (b) 4000 (c) 40000
  24. 24.Best estimate of 60 × 97? (a) 6000 (b) 60000 (c) 600
  25. 25.Best estimate of 92 × 80? (a) 72000 (b) 720 (c) 7200
  26. 26.Best estimate of 475 + 533? (a) 1000 (b) 1200 (c) 800
  27. 27.Best estimate of 12 × 26? (a) 30 (b) 300 (c) 3000
  28. 28.Best estimate of 836 + 357? (a) 1000 (b) 1200 (c) 1400
  29. 29.Best estimate of 80 × 37? (a) 320 (b) 32000 (c) 3200
  30. 30.Best estimate of 703 + 754? (a) 1700 (b) 1500 (c) 1300
  31. 31.Best estimate of 67 × 34? (a) 210 (b) 21000 (c) 2100
  32. 32.Best estimate of 76 × 79? (a) 640 (b) 64000 (c) 6400
  33. 33.Best estimate of 29 × 96? (a) 3000 (b) 30000 (c) 300
  34. 34.Best estimate of 30 × 91? (a) 27000 (b) 2700 (c) 270
  35. 35.Best estimate of 41 × 87? (a) 36000 (b) 360 (c) 3600
  36. 36.Best estimate of 197 + 286? (a) 300 (b) 500 (c) 700
  37. 37.Best estimate of 777 + 766? (a) 1400 (b) 1800 (c) 1600
  38. 38.Best estimate of 410 + 405? (a) 1000 (b) 800 (c) 600
  39. 39.Best estimate of 72 × 81? (a) 560 (b) 56000 (c) 5600
  40. 40.Best estimate of 88 × 31? (a) 27000 (b) 2700 (c) 270

Answer key

  1. 2400
  2. 2500
  3. 700
  4. 1000
  5. 2400
  6. 2400
  7. 900
  8. 1000
  9. 400
  10. 600
  11. 1100
  12. 600
  13. 2000
  14. 1600
  15. 1400
  16. 1400
  17. 1600
  18. 1500
  19. 700
  20. 700
  21. 700
  22. 3500
  23. 4000
  24. 6000
  25. 7200
  26. 1000
  27. 300
  28. 1200
  29. 3200
  30. 1500
  31. 2100
  32. 6400
  33. 3000
  34. 2700
  35. 3600
  36. 500
  37. 1600
  38. 800
  39. 5600
  40. 2700

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