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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 600 · 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 576 + 284? (a) 700 (b) 1100 (c) 900
  2. 2.Best estimate of 56 × 60? (a) 360 (b) 36000 (c) 3600
  3. 3.Best estimate of 316 + 251? (a) 600 (b) 400 (c) 800
  4. 4.Best estimate of 341 + 295? (a) 800 (b) 400 (c) 600
  5. 5.Best estimate of 622 + 376? (a) 1200 (b) 800 (c) 1000
  6. 6.Best estimate of 33 × 42? (a) 1200 (b) 120 (c) 12000
  7. 7.Best estimate of 845 + 196? (a) 1200 (b) 800 (c) 1000
  8. 8.Best estimate of 27 × 64? (a) 18000 (b) 1800 (c) 180
  9. 9.Best estimate of 97 × 74? (a) 700 (b) 7000 (c) 70000
  10. 10.Best estimate of 328 + 369? (a) 900 (b) 500 (c) 700
  11. 11.Best estimate of 39 × 86? (a) 360 (b) 36000 (c) 3600
  12. 12.Best estimate of 93 × 48? (a) 450 (b) 4500 (c) 45000
  13. 13.Best estimate of 32 × 40? (a) 1200 (b) 120 (c) 12000
  14. 14.Best estimate of 63 × 43? (a) 2400 (b) 240 (c) 24000
  15. 15.Best estimate of 839 + 458? (a) 1500 (b) 1100 (c) 1300
  16. 16.Best estimate of 66 × 71? (a) 4900 (b) 49000 (c) 490
  17. 17.Best estimate of 682 + 797? (a) 1500 (b) 1300 (c) 1700
  18. 18.Best estimate of 53 × 26? (a) 1500 (b) 15000 (c) 150
  19. 19.Best estimate of 47 × 77? (a) 400 (b) 40000 (c) 4000
  20. 20.Best estimate of 46 × 38? (a) 2000 (b) 20000 (c) 200
  21. 21.Best estimate of 97 × 20? (a) 200 (b) 20000 (c) 2000
  22. 22.Best estimate of 98 × 60? (a) 60000 (b) 600 (c) 6000
  23. 23.Best estimate of 506 + 717? (a) 1200 (b) 1400 (c) 1000
  24. 24.Best estimate of 297 + 613? (a) 900 (b) 1100 (c) 700
  25. 25.Best estimate of 54 × 32? (a) 1500 (b) 150 (c) 15000
  26. 26.Best estimate of 761 + 131? (a) 1100 (b) 900 (c) 700
  27. 27.Best estimate of 244 + 785? (a) 1200 (b) 800 (c) 1000
  28. 28.Best estimate of 805 + 578? (a) 1400 (b) 1600 (c) 1200
  29. 29.Best estimate of 522 + 225? (a) 900 (b) 500 (c) 700
  30. 30.Best estimate of 46 × 92? (a) 45000 (b) 450 (c) 4500
  31. 31.Best estimate of 489 + 232? (a) 700 (b) 900 (c) 500
  32. 32.Best estimate of 18 × 16? (a) 400 (b) 40 (c) 4000
  33. 33.Best estimate of 453 + 660? (a) 1200 (b) 1000 (c) 1400
  34. 34.Best estimate of 61 × 46? (a) 3000 (b) 300 (c) 30000
  35. 35.Best estimate of 33 × 92? (a) 27000 (b) 2700 (c) 270
  36. 36.Best estimate of 168 + 132? (a) 300 (b) 100 (c) 500
  37. 37.Best estimate of 693 + 868? (a) 1800 (b) 1400 (c) 1600
  38. 38.Best estimate of 79 × 16? (a) 16000 (b) 1600 (c) 160
  39. 39.Best estimate of 754 + 277? (a) 1100 (b) 900 (c) 1300
  40. 40.Best estimate of 86 × 41? (a) 3600 (b) 360 (c) 36000

Answer key

  1. 900
  2. 3600
  3. 600
  4. 600
  5. 1000
  6. 1200
  7. 1000
  8. 1800
  9. 7000
  10. 700
  11. 3600
  12. 4500
  13. 1200
  14. 2400
  15. 1300
  16. 4900
  17. 1500
  18. 1500
  19. 4000
  20. 2000
  21. 2000
  22. 6000
  23. 1200
  24. 900
  25. 1500
  26. 900
  27. 1000
  28. 1400
  29. 700
  30. 4500
  31. 700
  32. 400
  33. 1200
  34. 3000
  35. 2700
  36. 300
  37. 1600
  38. 1600
  39. 1100
  40. 3600

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