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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 827 · 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 56 × 24? (a) 120 (b) 1200 (c) 12000
  2. 2.Best estimate of 246 + 522? (a) 900 (b) 500 (c) 700
  3. 3.Best estimate of 18 × 44? (a) 80 (b) 800 (c) 8000
  4. 4.Best estimate of 158 + 534? (a) 700 (b) 500 (c) 900
  5. 5.Best estimate of 74 × 26? (a) 210 (b) 21000 (c) 2100
  6. 6.Best estimate of 33 × 36? (a) 12000 (b) 1200 (c) 120
  7. 7.Best estimate of 90 × 93? (a) 81000 (b) 810 (c) 8100
  8. 8.Best estimate of 73 × 52? (a) 350 (b) 3500 (c) 35000
  9. 9.Best estimate of 187 + 585? (a) 800 (b) 1000 (c) 600
  10. 10.Best estimate of 86 × 13? (a) 900 (b) 90 (c) 9000
  11. 11.Best estimate of 47 × 86? (a) 4500 (b) 45000 (c) 450
  12. 12.Best estimate of 96 × 78? (a) 800 (b) 80000 (c) 8000
  13. 13.Best estimate of 47 × 61? (a) 30000 (b) 3000 (c) 300
  14. 14.Best estimate of 36 × 49? (a) 20000 (b) 2000 (c) 200
  15. 15.Best estimate of 16 × 94? (a) 18000 (b) 1800 (c) 180
  16. 16.Best estimate of 29 × 13? (a) 3000 (b) 300 (c) 30
  17. 17.Best estimate of 82 × 66? (a) 560 (b) 5600 (c) 56000
  18. 18.Best estimate of 94 × 76? (a) 72000 (b) 720 (c) 7200
  19. 19.Best estimate of 629 + 267? (a) 1100 (b) 700 (c) 900
  20. 20.Best estimate of 51 × 44? (a) 2000 (b) 20000 (c) 200
  21. 21.Best estimate of 42 × 67? (a) 2800 (b) 28000 (c) 280
  22. 22.Best estimate of 88 × 68? (a) 6300 (b) 63000 (c) 630
  23. 23.Best estimate of 560 + 789? (a) 1600 (b) 1200 (c) 1400
  24. 24.Best estimate of 12 × 79? (a) 80 (b) 8000 (c) 800
  25. 25.Best estimate of 47 × 56? (a) 300 (b) 30000 (c) 3000
  26. 26.Best estimate of 30 × 36? (a) 1200 (b) 12000 (c) 120
  27. 27.Best estimate of 13 × 68? (a) 70 (b) 700 (c) 7000
  28. 28.Best estimate of 608 + 186? (a) 1000 (b) 800 (c) 600
  29. 29.Best estimate of 531 + 159? (a) 500 (b) 900 (c) 700
  30. 30.Best estimate of 91 × 26? (a) 270 (b) 2700 (c) 27000
  31. 31.Best estimate of 310 + 723? (a) 1200 (b) 800 (c) 1000
  32. 32.Best estimate of 249 + 559? (a) 1000 (b) 600 (c) 800
  33. 33.Best estimate of 41 × 42? (a) 160 (b) 16000 (c) 1600
  34. 34.Best estimate of 738 + 556? (a) 1100 (b) 1500 (c) 1300
  35. 35.Best estimate of 81 × 70? (a) 56000 (b) 560 (c) 5600
  36. 36.Best estimate of 51 × 97? (a) 50000 (b) 500 (c) 5000
  37. 37.Best estimate of 217 + 543? (a) 500 (b) 700 (c) 900
  38. 38.Best estimate of 59 × 83? (a) 48000 (b) 4800 (c) 480
  39. 39.Best estimate of 482 + 667? (a) 1000 (b) 1400 (c) 1200
  40. 40.Best estimate of 603 + 130? (a) 700 (b) 900 (c) 500

Answer key

  1. 1200
  2. 700
  3. 800
  4. 700
  5. 2100
  6. 1200
  7. 8100
  8. 3500
  9. 800
  10. 900
  11. 4500
  12. 8000
  13. 3000
  14. 2000
  15. 1800
  16. 300
  17. 5600
  18. 7200
  19. 900
  20. 2000
  21. 2800
  22. 6300
  23. 1400
  24. 800
  25. 3000
  26. 1200
  27. 700
  28. 800
  29. 700
  30. 2700
  31. 1000
  32. 800
  33. 1600
  34. 1300
  35. 5600
  36. 5000
  37. 700
  38. 4800
  39. 1200
  40. 700

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