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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 228 · 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 657 + 474? (a) 1200 (b) 1400 (c) 1000
  2. 2.Best estimate of 80 × 98? (a) 800 (b) 8000 (c) 80000
  3. 3.Best estimate of 273 + 851? (a) 1000 (b) 1400 (c) 1200
  4. 4.Best estimate of 42 × 26? (a) 12000 (b) 120 (c) 1200
  5. 5.Best estimate of 406 + 663? (a) 1300 (b) 1100 (c) 900
  6. 6.Best estimate of 710 + 446? (a) 900 (b) 1100 (c) 1300
  7. 7.Best estimate of 56 × 72? (a) 4200 (b) 42000 (c) 420
  8. 8.Best estimate of 84 × 88? (a) 7200 (b) 72000 (c) 720
  9. 9.Best estimate of 682 + 255? (a) 1200 (b) 800 (c) 1000
  10. 10.Best estimate of 18 × 89? (a) 18000 (b) 180 (c) 1800
  11. 11.Best estimate of 304 + 494? (a) 600 (b) 800 (c) 1000
  12. 12.Best estimate of 755 + 868? (a) 1700 (b) 1900 (c) 1500
  13. 13.Best estimate of 72 × 89? (a) 630 (b) 6300 (c) 63000
  14. 14.Best estimate of 52 × 50? (a) 25000 (b) 2500 (c) 250
  15. 15.Best estimate of 758 + 720? (a) 1300 (b) 1500 (c) 1700
  16. 16.Best estimate of 73 × 21? (a) 1400 (b) 14000 (c) 140
  17. 17.Best estimate of 88 × 30? (a) 2700 (b) 27000 (c) 270
  18. 18.Best estimate of 388 + 816? (a) 1200 (b) 1000 (c) 1400
  19. 19.Best estimate of 50 × 53? (a) 25000 (b) 2500 (c) 250
  20. 20.Best estimate of 93 × 29? (a) 2700 (b) 270 (c) 27000
  21. 21.Best estimate of 26 × 34? (a) 900 (b) 9000 (c) 90
  22. 22.Best estimate of 40 × 83? (a) 320 (b) 32000 (c) 3200
  23. 23.Best estimate of 63 × 71? (a) 42000 (b) 4200 (c) 420
  24. 24.Best estimate of 33 × 13? (a) 300 (b) 3000 (c) 30
  25. 25.Best estimate of 678 + 167? (a) 1100 (b) 700 (c) 900
  26. 26.Best estimate of 56 × 23? (a) 1200 (b) 12000 (c) 120
  27. 27.Best estimate of 31 × 66? (a) 2100 (b) 21000 (c) 210
  28. 28.Best estimate of 81 × 24? (a) 1600 (b) 16000 (c) 160
  29. 29.Best estimate of 82 × 13? (a) 8000 (b) 800 (c) 80
  30. 30.Best estimate of 82 × 74? (a) 5600 (b) 56000 (c) 560
  31. 31.Best estimate of 636 + 210? (a) 600 (b) 800 (c) 1000
  32. 32.Best estimate of 361 + 263? (a) 900 (b) 500 (c) 700
  33. 33.Best estimate of 48 × 43? (a) 2000 (b) 200 (c) 20000
  34. 34.Best estimate of 32 × 56? (a) 180 (b) 1800 (c) 18000
  35. 35.Best estimate of 52 × 29? (a) 1500 (b) 15000 (c) 150
  36. 36.Best estimate of 875 + 565? (a) 1500 (b) 1700 (c) 1300
  37. 37.Best estimate of 29 × 32? (a) 90 (b) 9000 (c) 900
  38. 38.Best estimate of 451 + 285? (a) 1000 (b) 800 (c) 600
  39. 39.Best estimate of 29 × 98? (a) 300 (b) 3000 (c) 30000
  40. 40.Best estimate of 26 × 29? (a) 9000 (b) 900 (c) 90

Answer key

  1. 1200
  2. 8000
  3. 1200
  4. 1200
  5. 1100
  6. 1100
  7. 4200
  8. 7200
  9. 1000
  10. 1800
  11. 800
  12. 1700
  13. 6300
  14. 2500
  15. 1500
  16. 1400
  17. 2700
  18. 1200
  19. 2500
  20. 2700
  21. 900
  22. 3200
  23. 4200
  24. 300
  25. 900
  26. 1200
  27. 2100
  28. 1600
  29. 800
  30. 5600
  31. 800
  32. 700
  33. 2000
  34. 1800
  35. 1500
  36. 1500
  37. 900
  38. 800
  39. 3000
  40. 900

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