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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 132 · 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 729 + 144? (a) 1000 (b) 800 (c) 600
  2. 2.Best estimate of 579 + 196? (a) 1000 (b) 600 (c) 800
  3. 3.Best estimate of 628 + 839? (a) 1600 (b) 1400 (c) 1200
  4. 4.Best estimate of 29 × 59? (a) 18000 (b) 180 (c) 1800
  5. 5.Best estimate of 248 + 863? (a) 1100 (b) 1300 (c) 900
  6. 6.Best estimate of 273 + 221? (a) 500 (b) 300 (c) 700
  7. 7.Best estimate of 86 × 91? (a) 81000 (b) 810 (c) 8100
  8. 8.Best estimate of 87 × 26? (a) 270 (b) 27000 (c) 2700
  9. 9.Best estimate of 415 + 517? (a) 700 (b) 1100 (c) 900
  10. 10.Best estimate of 164 + 185? (a) 200 (b) 600 (c) 400
  11. 11.Best estimate of 764 + 467? (a) 1100 (b) 1300 (c) 1500
  12. 12.Best estimate of 705 + 355? (a) 1300 (b) 1100 (c) 900
  13. 13.Best estimate of 94 × 82? (a) 72000 (b) 7200 (c) 720
  14. 14.Best estimate of 493 + 410? (a) 700 (b) 1100 (c) 900
  15. 15.Best estimate of 98 × 96? (a) 100000 (b) 10000 (c) 1000
  16. 16.Best estimate of 57 × 20? (a) 12000 (b) 1200 (c) 120
  17. 17.Best estimate of 251 + 503? (a) 800 (b) 1000 (c) 600
  18. 18.Best estimate of 267 + 829? (a) 1300 (b) 1100 (c) 900
  19. 19.Best estimate of 14 × 24? (a) 2000 (b) 200 (c) 20
  20. 20.Best estimate of 572 + 200? (a) 800 (b) 1000 (c) 600
  21. 21.Best estimate of 353 + 140? (a) 700 (b) 300 (c) 500
  22. 22.Best estimate of 69 × 30? (a) 21000 (b) 210 (c) 2100
  23. 23.Best estimate of 61 × 61? (a) 36000 (b) 3600 (c) 360
  24. 24.Best estimate of 84 × 42? (a) 32000 (b) 3200 (c) 320
  25. 25.Best estimate of 63 × 69? (a) 42000 (b) 420 (c) 4200
  26. 26.Best estimate of 433 + 620? (a) 1000 (b) 1200 (c) 800
  27. 27.Best estimate of 78 × 47? (a) 4000 (b) 40000 (c) 400
  28. 28.Best estimate of 36 × 44? (a) 1600 (b) 16000 (c) 160
  29. 29.Best estimate of 374 + 269? (a) 900 (b) 500 (c) 700
  30. 30.Best estimate of 736 + 592? (a) 1100 (b) 1500 (c) 1300
  31. 31.Best estimate of 81 × 66? (a) 560 (b) 5600 (c) 56000
  32. 32.Best estimate of 71 × 17? (a) 140 (b) 14000 (c) 1400
  33. 33.Best estimate of 42 × 17? (a) 80 (b) 8000 (c) 800
  34. 34.Best estimate of 51 × 36? (a) 20000 (b) 200 (c) 2000
  35. 35.Best estimate of 96 × 22? (a) 200 (b) 20000 (c) 2000
  36. 36.Best estimate of 47 × 87? (a) 4500 (b) 450 (c) 45000
  37. 37.Best estimate of 847 + 538? (a) 1100 (b) 1500 (c) 1300
  38. 38.Best estimate of 70 × 72? (a) 4900 (b) 490 (c) 49000
  39. 39.Best estimate of 843 + 290? (a) 900 (b) 1100 (c) 1300
  40. 40.Best estimate of 26 × 63? (a) 18000 (b) 180 (c) 1800

Answer key

  1. 800
  2. 800
  3. 1400
  4. 1800
  5. 1100
  6. 500
  7. 8100
  8. 2700
  9. 900
  10. 400
  11. 1300
  12. 1100
  13. 7200
  14. 900
  15. 10000
  16. 1200
  17. 800
  18. 1100
  19. 200
  20. 800
  21. 500
  22. 2100
  23. 3600
  24. 3200
  25. 4200
  26. 1000
  27. 4000
  28. 1600
  29. 700
  30. 1300
  31. 5600
  32. 1400
  33. 800
  34. 2000
  35. 2000
  36. 4500
  37. 1300
  38. 4900
  39. 1100
  40. 1800

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