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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 103 · 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 504 + 703? (a) 1200 (b) 1000 (c) 1400
  2. 2.Best estimate of 262 + 262? (a) 400 (b) 800 (c) 600
  3. 3.Best estimate of 13 × 42? (a) 400 (b) 40 (c) 4000
  4. 4.Best estimate of 18 × 73? (a) 1400 (b) 140 (c) 14000
  5. 5.Best estimate of 32 × 16? (a) 600 (b) 60 (c) 6000
  6. 6.Best estimate of 87 × 41? (a) 360 (b) 3600 (c) 36000
  7. 7.Best estimate of 177 + 133? (a) 500 (b) 300 (c) 100
  8. 8.Best estimate of 709 + 744? (a) 1400 (b) 1200 (c) 1600
  9. 9.Best estimate of 59 × 49? (a) 300 (b) 3000 (c) 30000
  10. 10.Best estimate of 83 × 60? (a) 4800 (b) 480 (c) 48000
  11. 11.Best estimate of 70 × 63? (a) 42000 (b) 4200 (c) 420
  12. 12.Best estimate of 443 + 338? (a) 900 (b) 700 (c) 500
  13. 13.Best estimate of 20 × 72? (a) 1400 (b) 140 (c) 14000
  14. 14.Best estimate of 94 × 47? (a) 4500 (b) 45000 (c) 450
  15. 15.Best estimate of 64 × 59? (a) 36000 (b) 3600 (c) 360
  16. 16.Best estimate of 429 + 318? (a) 900 (b) 500 (c) 700
  17. 17.Best estimate of 36 × 63? (a) 2400 (b) 240 (c) 24000
  18. 18.Best estimate of 534 + 202? (a) 700 (b) 500 (c) 900
  19. 19.Best estimate of 93 × 32? (a) 27000 (b) 270 (c) 2700
  20. 20.Best estimate of 796 + 831? (a) 1400 (b) 1800 (c) 1600
  21. 21.Best estimate of 81 × 86? (a) 720 (b) 72000 (c) 7200
  22. 22.Best estimate of 34 × 41? (a) 120 (b) 12000 (c) 1200
  23. 23.Best estimate of 89 × 22? (a) 180 (b) 1800 (c) 18000
  24. 24.Best estimate of 56 × 41? (a) 24000 (b) 2400 (c) 240
  25. 25.Best estimate of 76 × 16? (a) 160 (b) 1600 (c) 16000
  26. 26.Best estimate of 753 + 312? (a) 1100 (b) 900 (c) 1300
  27. 27.Best estimate of 327 + 615? (a) 700 (b) 900 (c) 1100
  28. 28.Best estimate of 700 + 873? (a) 1600 (b) 1400 (c) 1800
  29. 29.Best estimate of 67 × 97? (a) 7000 (b) 700 (c) 70000
  30. 30.Best estimate of 30 × 44? (a) 12000 (b) 120 (c) 1200
  31. 31.Best estimate of 674 + 278? (a) 800 (b) 1200 (c) 1000
  32. 32.Best estimate of 86 × 79? (a) 72000 (b) 720 (c) 7200
  33. 33.Best estimate of 211 + 645? (a) 1000 (b) 600 (c) 800
  34. 34.Best estimate of 30 × 66? (a) 2100 (b) 21000 (c) 210
  35. 35.Best estimate of 298 + 758? (a) 900 (b) 1300 (c) 1100
  36. 36.Best estimate of 50 × 34? (a) 150 (b) 1500 (c) 15000
  37. 37.Best estimate of 86 × 83? (a) 7200 (b) 720 (c) 72000
  38. 38.Best estimate of 93 × 48? (a) 450 (b) 4500 (c) 45000
  39. 39.Best estimate of 51 × 94? (a) 4500 (b) 45000 (c) 450
  40. 40.Best estimate of 29 × 46? (a) 150 (b) 15000 (c) 1500

Answer key

  1. 1200
  2. 600
  3. 400
  4. 1400
  5. 600
  6. 3600
  7. 300
  8. 1400
  9. 3000
  10. 4800
  11. 4200
  12. 700
  13. 1400
  14. 4500
  15. 3600
  16. 700
  17. 2400
  18. 700
  19. 2700
  20. 1600
  21. 7200
  22. 1200
  23. 1800
  24. 2400
  25. 1600
  26. 1100
  27. 900
  28. 1600
  29. 7000
  30. 1200
  31. 1000
  32. 7200
  33. 800
  34. 2100
  35. 1100
  36. 1500
  37. 7200
  38. 4500
  39. 4500
  40. 1500

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