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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 453 · 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 36 × 46? (a) 20000 (b) 2000 (c) 200
  2. 2.Best estimate of 492 + 338? (a) 1000 (b) 800 (c) 600
  3. 3.Best estimate of 746 + 762? (a) 1300 (b) 1500 (c) 1700
  4. 4.Best estimate of 376 + 733? (a) 1100 (b) 1300 (c) 900
  5. 5.Best estimate of 58 × 18? (a) 1200 (b) 120 (c) 12000
  6. 6.Best estimate of 88 × 88? (a) 810 (b) 81000 (c) 8100
  7. 7.Best estimate of 89 × 18? (a) 18000 (b) 1800 (c) 180
  8. 8.Best estimate of 501 + 235? (a) 900 (b) 500 (c) 700
  9. 9.Best estimate of 60 × 54? (a) 3000 (b) 300 (c) 30000
  10. 10.Best estimate of 93 × 72? (a) 6300 (b) 630 (c) 63000
  11. 11.Best estimate of 383 + 751? (a) 1200 (b) 1400 (c) 1000
  12. 12.Best estimate of 638 + 309? (a) 700 (b) 900 (c) 1100
  13. 13.Best estimate of 332 + 188? (a) 700 (b) 300 (c) 500
  14. 14.Best estimate of 193 + 121? (a) 300 (b) 100 (c) 500
  15. 15.Best estimate of 493 + 410? (a) 900 (b) 700 (c) 1100
  16. 16.Best estimate of 245 + 333? (a) 300 (b) 500 (c) 700
  17. 17.Best estimate of 31 × 26? (a) 9000 (b) 90 (c) 900
  18. 18.Best estimate of 139 + 311? (a) 400 (b) 200 (c) 600
  19. 19.Best estimate of 39 × 60? (a) 240 (b) 2400 (c) 24000
  20. 20.Best estimate of 16 × 54? (a) 10000 (b) 100 (c) 1000
  21. 21.Best estimate of 406 + 332? (a) 900 (b) 700 (c) 500
  22. 22.Best estimate of 339 + 282? (a) 400 (b) 800 (c) 600
  23. 23.Best estimate of 734 + 528? (a) 1200 (b) 1400 (c) 1000
  24. 24.Best estimate of 26 × 38? (a) 1200 (b) 12000 (c) 120
  25. 25.Best estimate of 581 + 236? (a) 800 (b) 600 (c) 1000
  26. 26.Best estimate of 319 + 304? (a) 600 (b) 800 (c) 400
  27. 27.Best estimate of 98 × 96? (a) 100000 (b) 1000 (c) 10000
  28. 28.Best estimate of 58 × 97? (a) 6000 (b) 600 (c) 60000
  29. 29.Best estimate of 494 + 626? (a) 1100 (b) 900 (c) 1300
  30. 30.Best estimate of 54 × 39? (a) 2000 (b) 20000 (c) 200
  31. 31.Best estimate of 140 + 330? (a) 600 (b) 400 (c) 200
  32. 32.Best estimate of 829 + 324? (a) 900 (b) 1100 (c) 1300
  33. 33.Best estimate of 352 + 783? (a) 1400 (b) 1000 (c) 1200
  34. 34.Best estimate of 630 + 190? (a) 800 (b) 600 (c) 1000
  35. 35.Best estimate of 799 + 476? (a) 1500 (b) 1300 (c) 1100
  36. 36.Best estimate of 22 × 16? (a) 4000 (b) 400 (c) 40
  37. 37.Best estimate of 31 × 21? (a) 60 (b) 600 (c) 6000
  38. 38.Best estimate of 40 × 56? (a) 2400 (b) 24000 (c) 240
  39. 39.Best estimate of 73 × 17? (a) 1400 (b) 14000 (c) 140
  40. 40.Best estimate of 98 × 20? (a) 2000 (b) 200 (c) 20000

Answer key

  1. 2000
  2. 800
  3. 1500
  4. 1100
  5. 1200
  6. 8100
  7. 1800
  8. 700
  9. 3000
  10. 6300
  11. 1200
  12. 900
  13. 500
  14. 300
  15. 900
  16. 500
  17. 900
  18. 400
  19. 2400
  20. 1000
  21. 700
  22. 600
  23. 1200
  24. 1200
  25. 800
  26. 600
  27. 10000
  28. 6000
  29. 1100
  30. 2000
  31. 400
  32. 1100
  33. 1200
  34. 800
  35. 1300
  36. 400
  37. 600
  38. 2400
  39. 1400
  40. 2000

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