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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 982 · 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 757 + 625? (a) 1200 (b) 1600 (c) 1400
  2. 2.Best estimate of 517 + 237? (a) 900 (b) 700 (c) 500
  3. 3.Best estimate of 249 + 724? (a) 700 (b) 1100 (c) 900
  4. 4.Best estimate of 512 + 640? (a) 1100 (b) 900 (c) 1300
  5. 5.Best estimate of 84 × 36? (a) 3200 (b) 320 (c) 32000
  6. 6.Best estimate of 72 × 12? (a) 700 (b) 70 (c) 7000
  7. 7.Best estimate of 80 × 42? (a) 32000 (b) 320 (c) 3200
  8. 8.Best estimate of 59 × 24? (a) 120 (b) 1200 (c) 12000
  9. 9.Best estimate of 294 + 217? (a) 500 (b) 700 (c) 300
  10. 10.Best estimate of 78 × 51? (a) 40000 (b) 4000 (c) 400
  11. 11.Best estimate of 465 + 198? (a) 500 (b) 700 (c) 900
  12. 12.Best estimate of 62 × 42? (a) 240 (b) 2400 (c) 24000
  13. 13.Best estimate of 336 + 264? (a) 800 (b) 600 (c) 400
  14. 14.Best estimate of 121 + 630? (a) 700 (b) 500 (c) 900
  15. 15.Best estimate of 829 + 773? (a) 1600 (b) 1400 (c) 1800
  16. 16.Best estimate of 631 + 372? (a) 800 (b) 1000 (c) 1200
  17. 17.Best estimate of 440 + 680? (a) 1100 (b) 1300 (c) 900
  18. 18.Best estimate of 26 × 19? (a) 60 (b) 600 (c) 6000
  19. 19.Best estimate of 839 + 360? (a) 1200 (b) 1000 (c) 1400
  20. 20.Best estimate of 74 × 46? (a) 3500 (b) 35000 (c) 350
  21. 21.Best estimate of 24 × 52? (a) 100 (b) 1000 (c) 10000
  22. 22.Best estimate of 428 + 652? (a) 1100 (b) 1300 (c) 900
  23. 23.Best estimate of 872 + 329? (a) 1400 (b) 1000 (c) 1200
  24. 24.Best estimate of 97 × 48? (a) 5000 (b) 50000 (c) 500
  25. 25.Best estimate of 79 × 76? (a) 6400 (b) 640 (c) 64000
  26. 26.Best estimate of 70 × 23? (a) 1400 (b) 140 (c) 14000
  27. 27.Best estimate of 439 + 638? (a) 800 (b) 1200 (c) 1000
  28. 28.Best estimate of 46 × 42? (a) 200 (b) 20000 (c) 2000
  29. 29.Best estimate of 174 + 753? (a) 1200 (b) 800 (c) 1000
  30. 30.Best estimate of 346 + 643? (a) 1100 (b) 900 (c) 700
  31. 31.Best estimate of 16 × 12? (a) 200 (b) 2000 (c) 20
  32. 32.Best estimate of 286 + 862? (a) 1000 (b) 1200 (c) 1400
  33. 33.Best estimate of 37 × 56? (a) 2400 (b) 240 (c) 24000
  34. 34.Best estimate of 505 + 216? (a) 900 (b) 500 (c) 700
  35. 35.Best estimate of 620 + 199? (a) 800 (b) 600 (c) 1000
  36. 36.Best estimate of 583 + 424? (a) 1000 (b) 1200 (c) 800
  37. 37.Best estimate of 327 + 866? (a) 1400 (b) 1200 (c) 1000
  38. 38.Best estimate of 47 × 98? (a) 500 (b) 50000 (c) 5000
  39. 39.Best estimate of 651 + 396? (a) 900 (b) 1100 (c) 1300
  40. 40.Best estimate of 51 × 68? (a) 350 (b) 3500 (c) 35000

Answer key

  1. 1400
  2. 700
  3. 900
  4. 1100
  5. 3200
  6. 700
  7. 3200
  8. 1200
  9. 500
  10. 4000
  11. 700
  12. 2400
  13. 600
  14. 700
  15. 1600
  16. 1000
  17. 1100
  18. 600
  19. 1200
  20. 3500
  21. 1000
  22. 1100
  23. 1200
  24. 5000
  25. 6400
  26. 1400
  27. 1000
  28. 2000
  29. 1000
  30. 900
  31. 200
  32. 1200
  33. 2400
  34. 700
  35. 800
  36. 1000
  37. 1200
  38. 5000
  39. 1100
  40. 3500

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