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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 527 · 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 156 + 564? (a) 1000 (b) 600 (c) 800
  2. 2.Best estimate of 874 + 691? (a) 1600 (b) 1400 (c) 1800
  3. 3.Best estimate of 59 × 16? (a) 120 (b) 1200 (c) 12000
  4. 4.Best estimate of 701 + 255? (a) 1200 (b) 1000 (c) 800
  5. 5.Best estimate of 627 + 293? (a) 1100 (b) 900 (c) 700
  6. 6.Best estimate of 96 × 16? (a) 2000 (b) 200 (c) 20000
  7. 7.Best estimate of 880 + 268? (a) 1400 (b) 1200 (c) 1000
  8. 8.Best estimate of 609 + 137? (a) 900 (b) 500 (c) 700
  9. 9.Best estimate of 305 + 479? (a) 600 (b) 800 (c) 1000
  10. 10.Best estimate of 36 × 31? (a) 1200 (b) 120 (c) 12000
  11. 11.Best estimate of 316 + 165? (a) 300 (b) 700 (c) 500
  12. 12.Best estimate of 61 × 22? (a) 1200 (b) 12000 (c) 120
  13. 13.Best estimate of 333 + 556? (a) 900 (b) 700 (c) 1100
  14. 14.Best estimate of 214 + 552? (a) 800 (b) 600 (c) 1000
  15. 15.Best estimate of 72 × 34? (a) 210 (b) 21000 (c) 2100
  16. 16.Best estimate of 409 + 303? (a) 900 (b) 700 (c) 500
  17. 17.Best estimate of 58 × 48? (a) 3000 (b) 300 (c) 30000
  18. 18.Best estimate of 96 × 97? (a) 100000 (b) 1000 (c) 10000
  19. 19.Best estimate of 811 + 736? (a) 1300 (b) 1500 (c) 1700
  20. 20.Best estimate of 28 × 62? (a) 180 (b) 1800 (c) 18000
  21. 21.Best estimate of 520 + 171? (a) 500 (b) 900 (c) 700
  22. 22.Best estimate of 33 × 37? (a) 12000 (b) 1200 (c) 120
  23. 23.Best estimate of 30 × 36? (a) 120 (b) 1200 (c) 12000
  24. 24.Best estimate of 649 + 782? (a) 1400 (b) 1600 (c) 1200
  25. 25.Best estimate of 458 + 880? (a) 1400 (b) 1200 (c) 1600
  26. 26.Best estimate of 49 × 41? (a) 20000 (b) 200 (c) 2000
  27. 27.Best estimate of 86 × 17? (a) 1800 (b) 18000 (c) 180
  28. 28.Best estimate of 451 + 247? (a) 900 (b) 700 (c) 500
  29. 29.Best estimate of 16 × 36? (a) 8000 (b) 800 (c) 80
  30. 30.Best estimate of 74 × 42? (a) 280 (b) 28000 (c) 2800
  31. 31.Best estimate of 600 + 735? (a) 1300 (b) 1100 (c) 1500
  32. 32.Best estimate of 633 + 641? (a) 1000 (b) 1400 (c) 1200
  33. 33.Best estimate of 668 + 853? (a) 1400 (b) 1800 (c) 1600
  34. 34.Best estimate of 97 × 41? (a) 4000 (b) 40000 (c) 400
  35. 35.Best estimate of 26 × 88? (a) 2700 (b) 27000 (c) 270
  36. 36.Best estimate of 12 × 48? (a) 500 (b) 5000 (c) 50
  37. 37.Best estimate of 44 × 97? (a) 400 (b) 4000 (c) 40000
  38. 38.Best estimate of 27 × 46? (a) 1500 (b) 15000 (c) 150
  39. 39.Best estimate of 666 + 821? (a) 1300 (b) 1500 (c) 1700
  40. 40.Best estimate of 785 + 547? (a) 1500 (b) 1300 (c) 1100

Answer key

  1. 800
  2. 1600
  3. 1200
  4. 1000
  5. 900
  6. 2000
  7. 1200
  8. 700
  9. 800
  10. 1200
  11. 500
  12. 1200
  13. 900
  14. 800
  15. 2100
  16. 700
  17. 3000
  18. 10000
  19. 1500
  20. 1800
  21. 700
  22. 1200
  23. 1200
  24. 1400
  25. 1400
  26. 2000
  27. 1800
  28. 700
  29. 800
  30. 2800
  31. 1300
  32. 1200
  33. 1600
  34. 4000
  35. 2700
  36. 500
  37. 4000
  38. 1500
  39. 1500
  40. 1300

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