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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 248 · 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 62 × 22? (a) 1200 (b) 12000 (c) 120
  2. 2.Best estimate of 271 + 255? (a) 800 (b) 400 (c) 600
  3. 3.Best estimate of 476 + 280? (a) 1000 (b) 800 (c) 600
  4. 4.Best estimate of 770 + 282? (a) 1100 (b) 1300 (c) 900
  5. 5.Best estimate of 12 × 22? (a) 20 (b) 2000 (c) 200
  6. 6.Best estimate of 195 + 700? (a) 900 (b) 1100 (c) 700
  7. 7.Best estimate of 438 + 495? (a) 1100 (b) 900 (c) 700
  8. 8.Best estimate of 87 × 13? (a) 9000 (b) 900 (c) 90
  9. 9.Best estimate of 57 × 26? (a) 18000 (b) 180 (c) 1800
  10. 10.Best estimate of 47 × 26? (a) 1500 (b) 15000 (c) 150
  11. 11.Best estimate of 47 × 31? (a) 15000 (b) 1500 (c) 150
  12. 12.Best estimate of 467 + 779? (a) 1300 (b) 1100 (c) 1500
  13. 13.Best estimate of 33 × 39? (a) 120 (b) 1200 (c) 12000
  14. 14.Best estimate of 695 + 688? (a) 1200 (b) 1400 (c) 1600
  15. 15.Best estimate of 277 + 235? (a) 700 (b) 500 (c) 300
  16. 16.Best estimate of 16 × 26? (a) 6000 (b) 600 (c) 60
  17. 17.Best estimate of 33 × 21? (a) 6000 (b) 600 (c) 60
  18. 18.Best estimate of 200 + 791? (a) 1000 (b) 800 (c) 1200
  19. 19.Best estimate of 22 × 26? (a) 600 (b) 6000 (c) 60
  20. 20.Best estimate of 819 + 852? (a) 1900 (b) 1700 (c) 1500
  21. 21.Best estimate of 28 × 57? (a) 180 (b) 18000 (c) 1800
  22. 22.Best estimate of 666 + 364? (a) 1100 (b) 1300 (c) 900
  23. 23.Best estimate of 12 × 77? (a) 8000 (b) 80 (c) 800
  24. 24.Best estimate of 26 × 19? (a) 600 (b) 6000 (c) 60
  25. 25.Best estimate of 187 + 231? (a) 600 (b) 400 (c) 200
  26. 26.Best estimate of 32 × 78? (a) 240 (b) 2400 (c) 24000
  27. 27.Best estimate of 83 × 36? (a) 3200 (b) 320 (c) 32000
  28. 28.Best estimate of 90 × 40? (a) 360 (b) 36000 (c) 3600
  29. 29.Best estimate of 727 + 738? (a) 1600 (b) 1200 (c) 1400
  30. 30.Best estimate of 96 × 42? (a) 4000 (b) 400 (c) 40000
  31. 31.Best estimate of 803 + 486? (a) 1500 (b) 1300 (c) 1100
  32. 32.Best estimate of 76 × 20? (a) 1600 (b) 160 (c) 16000
  33. 33.Best estimate of 17 × 54? (a) 1000 (b) 10000 (c) 100
  34. 34.Best estimate of 346 + 324? (a) 800 (b) 400 (c) 600
  35. 35.Best estimate of 71 × 81? (a) 560 (b) 5600 (c) 56000
  36. 36.Best estimate of 62 × 69? (a) 4200 (b) 420 (c) 42000
  37. 37.Best estimate of 736 + 476? (a) 1400 (b) 1200 (c) 1000
  38. 38.Best estimate of 476 + 481? (a) 1000 (b) 1200 (c) 800
  39. 39.Best estimate of 503 + 451? (a) 1200 (b) 800 (c) 1000
  40. 40.Best estimate of 16 × 41? (a) 8000 (b) 800 (c) 80

Answer key

  1. 1200
  2. 600
  3. 800
  4. 1100
  5. 200
  6. 900
  7. 900
  8. 900
  9. 1800
  10. 1500
  11. 1500
  12. 1300
  13. 1200
  14. 1400
  15. 500
  16. 600
  17. 600
  18. 1000
  19. 600
  20. 1700
  21. 1800
  22. 1100
  23. 800
  24. 600
  25. 400
  26. 2400
  27. 3200
  28. 3600
  29. 1400
  30. 4000
  31. 1300
  32. 1600
  33. 1000
  34. 600
  35. 5600
  36. 4200
  37. 1200
  38. 1000
  39. 1000
  40. 800

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