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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 572 · 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 718 + 562? (a) 1100 (b) 1500 (c) 1300
  2. 2.Best estimate of 44 × 73? (a) 280 (b) 28000 (c) 2800
  3. 3.Best estimate of 67 × 42? (a) 28000 (b) 2800 (c) 280
  4. 4.Best estimate of 26 × 69? (a) 2100 (b) 21000 (c) 210
  5. 5.Best estimate of 248 + 582? (a) 1000 (b) 800 (c) 600
  6. 6.Best estimate of 665 + 373? (a) 1100 (b) 900 (c) 1300
  7. 7.Best estimate of 48 × 12? (a) 50 (b) 5000 (c) 500
  8. 8.Best estimate of 37 × 34? (a) 12000 (b) 120 (c) 1200
  9. 9.Best estimate of 388 + 198? (a) 800 (b) 400 (c) 600
  10. 10.Best estimate of 30 × 21? (a) 60 (b) 600 (c) 6000
  11. 11.Best estimate of 616 + 528? (a) 1300 (b) 1100 (c) 900
  12. 12.Best estimate of 56 × 50? (a) 300 (b) 30000 (c) 3000
  13. 13.Best estimate of 545 + 429? (a) 1100 (b) 700 (c) 900
  14. 14.Best estimate of 24 × 12? (a) 200 (b) 20 (c) 2000
  15. 15.Best estimate of 196 + 327? (a) 300 (b) 500 (c) 700
  16. 16.Best estimate of 251 + 681? (a) 1200 (b) 1000 (c) 800
  17. 17.Best estimate of 707 + 666? (a) 1400 (b) 1200 (c) 1600
  18. 18.Best estimate of 343 + 611? (a) 900 (b) 700 (c) 1100
  19. 19.Best estimate of 480 + 336? (a) 600 (b) 1000 (c) 800
  20. 20.Best estimate of 511 + 451? (a) 800 (b) 1000 (c) 1200
  21. 21.Best estimate of 481 + 792? (a) 1300 (b) 1500 (c) 1100
  22. 22.Best estimate of 194 + 476? (a) 500 (b) 900 (c) 700
  23. 23.Best estimate of 12 × 44? (a) 4000 (b) 40 (c) 400
  24. 24.Best estimate of 39 × 80? (a) 3200 (b) 32000 (c) 320
  25. 25.Best estimate of 53 × 30? (a) 1500 (b) 150 (c) 15000
  26. 26.Best estimate of 76 × 56? (a) 4800 (b) 48000 (c) 480
  27. 27.Best estimate of 316 + 742? (a) 800 (b) 1200 (c) 1000
  28. 28.Best estimate of 50 × 61? (a) 300 (b) 30000 (c) 3000
  29. 29.Best estimate of 86 × 52? (a) 450 (b) 4500 (c) 45000
  30. 30.Best estimate of 56 × 12? (a) 6000 (b) 600 (c) 60
  31. 31.Best estimate of 30 × 62? (a) 1800 (b) 18000 (c) 180
  32. 32.Best estimate of 849 + 340? (a) 1100 (b) 900 (c) 1300
  33. 33.Best estimate of 91 × 59? (a) 54000 (b) 540 (c) 5400
  34. 34.Best estimate of 324 + 561? (a) 900 (b) 1100 (c) 700
  35. 35.Best estimate of 38 × 47? (a) 2000 (b) 200 (c) 20000
  36. 36.Best estimate of 602 + 321? (a) 900 (b) 1100 (c) 700
  37. 37.Best estimate of 53 × 81? (a) 4000 (b) 40000 (c) 400
  38. 38.Best estimate of 518 + 138? (a) 800 (b) 600 (c) 400
  39. 39.Best estimate of 587 + 276? (a) 700 (b) 1100 (c) 900
  40. 40.Best estimate of 61 × 56? (a) 360 (b) 36000 (c) 3600

Answer key

  1. 1300
  2. 2800
  3. 2800
  4. 2100
  5. 800
  6. 1100
  7. 500
  8. 1200
  9. 600
  10. 600
  11. 1100
  12. 3000
  13. 900
  14. 200
  15. 500
  16. 1000
  17. 1400
  18. 900
  19. 800
  20. 1000
  21. 1300
  22. 700
  23. 400
  24. 3200
  25. 1500
  26. 4800
  27. 1000
  28. 3000
  29. 4500
  30. 600
  31. 1800
  32. 1100
  33. 5400
  34. 900
  35. 2000
  36. 900
  37. 4000
  38. 600
  39. 900
  40. 3600

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