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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 762 · 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 455 + 264? (a) 600 (b) 800 (c) 1000
  2. 2.Best estimate of 39 × 91? (a) 3600 (b) 36000 (c) 360
  3. 3.Best estimate of 49 × 94? (a) 450 (b) 45000 (c) 4500
  4. 4.Best estimate of 32 × 40? (a) 120 (b) 12000 (c) 1200
  5. 5.Best estimate of 161 + 736? (a) 900 (b) 1100 (c) 700
  6. 6.Best estimate of 34 × 52? (a) 1500 (b) 150 (c) 15000
  7. 7.Best estimate of 777 + 506? (a) 1300 (b) 1500 (c) 1100
  8. 8.Best estimate of 317 + 754? (a) 1100 (b) 900 (c) 1300
  9. 9.Best estimate of 70 × 89? (a) 63000 (b) 6300 (c) 630
  10. 10.Best estimate of 80 × 37? (a) 320 (b) 32000 (c) 3200
  11. 11.Best estimate of 154 + 768? (a) 1200 (b) 800 (c) 1000
  12. 12.Best estimate of 89 × 92? (a) 810 (b) 81000 (c) 8100
  13. 13.Best estimate of 16 × 89? (a) 18000 (b) 1800 (c) 180
  14. 14.Best estimate of 22 × 27? (a) 600 (b) 60 (c) 6000
  15. 15.Best estimate of 83 × 87? (a) 72000 (b) 720 (c) 7200
  16. 16.Best estimate of 24 × 92? (a) 1800 (b) 18000 (c) 180
  17. 17.Best estimate of 697 + 718? (a) 1200 (b) 1600 (c) 1400
  18. 18.Best estimate of 22 × 92? (a) 1800 (b) 18000 (c) 180
  19. 19.Best estimate of 394 + 407? (a) 600 (b) 1000 (c) 800
  20. 20.Best estimate of 27 × 91? (a) 27000 (b) 2700 (c) 270
  21. 21.Best estimate of 49 × 50? (a) 25000 (b) 250 (c) 2500
  22. 22.Best estimate of 791 + 163? (a) 800 (b) 1000 (c) 1200
  23. 23.Best estimate of 493 + 407? (a) 700 (b) 900 (c) 1100
  24. 24.Best estimate of 90 × 74? (a) 63000 (b) 6300 (c) 630
  25. 25.Best estimate of 537 + 737? (a) 1000 (b) 1400 (c) 1200
  26. 26.Best estimate of 79 × 26? (a) 240 (b) 24000 (c) 2400
  27. 27.Best estimate of 93 × 51? (a) 450 (b) 4500 (c) 45000
  28. 28.Best estimate of 60 × 13? (a) 60 (b) 6000 (c) 600
  29. 29.Best estimate of 560 + 177? (a) 600 (b) 1000 (c) 800
  30. 30.Best estimate of 24 × 16? (a) 40 (b) 4000 (c) 400
  31. 31.Best estimate of 198 + 247? (a) 400 (b) 600 (c) 200
  32. 32.Best estimate of 12 × 27? (a) 3000 (b) 300 (c) 30
  33. 33.Best estimate of 43 × 86? (a) 360 (b) 36000 (c) 3600
  34. 34.Best estimate of 286 + 236? (a) 300 (b) 500 (c) 700
  35. 35.Best estimate of 92 × 56? (a) 54000 (b) 540 (c) 5400
  36. 36.Best estimate of 33 × 21? (a) 6000 (b) 60 (c) 600
  37. 37.Best estimate of 69 × 17? (a) 14000 (b) 1400 (c) 140
  38. 38.Best estimate of 746 + 163? (a) 700 (b) 900 (c) 1100
  39. 39.Best estimate of 504 + 784? (a) 1300 (b) 1500 (c) 1100
  40. 40.Best estimate of 44 × 91? (a) 3600 (b) 360 (c) 36000

Answer key

  1. 800
  2. 3600
  3. 4500
  4. 1200
  5. 900
  6. 1500
  7. 1300
  8. 1100
  9. 6300
  10. 3200
  11. 1000
  12. 8100
  13. 1800
  14. 600
  15. 7200
  16. 1800
  17. 1400
  18. 1800
  19. 800
  20. 2700
  21. 2500
  22. 1000
  23. 900
  24. 6300
  25. 1200
  26. 2400
  27. 4500
  28. 600
  29. 800
  30. 400
  31. 400
  32. 300
  33. 3600
  34. 500
  35. 5400
  36. 600
  37. 1400
  38. 900
  39. 1300
  40. 3600

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