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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 517 · 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 16 × 66? (a) 1400 (b) 14000 (c) 140
  2. 2.Best estimate of 734 + 310? (a) 1000 (b) 1200 (c) 800
  3. 3.Best estimate of 80 × 62? (a) 48000 (b) 4800 (c) 480
  4. 4.Best estimate of 90 × 34? (a) 270 (b) 27000 (c) 2700
  5. 5.Best estimate of 36 × 47? (a) 2000 (b) 200 (c) 20000
  6. 6.Best estimate of 354 + 542? (a) 900 (b) 700 (c) 1100
  7. 7.Best estimate of 746 + 198? (a) 700 (b) 900 (c) 1100
  8. 8.Best estimate of 51 × 70? (a) 350 (b) 35000 (c) 3500
  9. 9.Best estimate of 238 + 159? (a) 600 (b) 400 (c) 200
  10. 10.Best estimate of 388 + 322? (a) 700 (b) 900 (c) 500
  11. 11.Best estimate of 448 + 474? (a) 900 (b) 1100 (c) 700
  12. 12.Best estimate of 207 + 763? (a) 1200 (b) 1000 (c) 800
  13. 13.Best estimate of 46 × 31? (a) 150 (b) 15000 (c) 1500
  14. 14.Best estimate of 706 + 716? (a) 1200 (b) 1600 (c) 1400
  15. 15.Best estimate of 36 × 29? (a) 12000 (b) 1200 (c) 120
  16. 16.Best estimate of 451 + 366? (a) 700 (b) 1100 (c) 900
  17. 17.Best estimate of 81 × 27? (a) 240 (b) 24000 (c) 2400
  18. 18.Best estimate of 16 × 26? (a) 6000 (b) 60 (c) 600
  19. 19.Best estimate of 142 + 330? (a) 600 (b) 200 (c) 400
  20. 20.Best estimate of 64 × 96? (a) 600 (b) 60000 (c) 6000
  21. 21.Best estimate of 560 + 598? (a) 1000 (b) 1200 (c) 1400
  22. 22.Best estimate of 629 + 451? (a) 1100 (b) 900 (c) 1300
  23. 23.Best estimate of 788 + 188? (a) 800 (b) 1200 (c) 1000
  24. 24.Best estimate of 12 × 86? (a) 900 (b) 9000 (c) 90
  25. 25.Best estimate of 189 + 829? (a) 800 (b) 1200 (c) 1000
  26. 26.Best estimate of 94 × 23? (a) 18000 (b) 180 (c) 1800
  27. 27.Best estimate of 90 × 32? (a) 2700 (b) 27000 (c) 270
  28. 28.Best estimate of 66 × 17? (a) 1400 (b) 140 (c) 14000
  29. 29.Best estimate of 50 × 90? (a) 4500 (b) 450 (c) 45000
  30. 30.Best estimate of 80 × 38? (a) 320 (b) 3200 (c) 32000
  31. 31.Best estimate of 17 × 72? (a) 1400 (b) 140 (c) 14000
  32. 32.Best estimate of 36 × 24? (a) 8000 (b) 80 (c) 800
  33. 33.Best estimate of 32 × 26? (a) 9000 (b) 90 (c) 900
  34. 34.Best estimate of 419 + 454? (a) 700 (b) 1100 (c) 900
  35. 35.Best estimate of 36 × 71? (a) 2800 (b) 28000 (c) 280
  36. 36.Best estimate of 24 × 58? (a) 120 (b) 12000 (c) 1200
  37. 37.Best estimate of 54 × 50? (a) 250 (b) 2500 (c) 25000
  38. 38.Best estimate of 311 + 877? (a) 1200 (b) 1400 (c) 1000
  39. 39.Best estimate of 283 + 730? (a) 1000 (b) 1200 (c) 800
  40. 40.Best estimate of 67 × 13? (a) 7000 (b) 70 (c) 700

Answer key

  1. 1400
  2. 1000
  3. 4800
  4. 2700
  5. 2000
  6. 900
  7. 900
  8. 3500
  9. 400
  10. 700
  11. 900
  12. 1000
  13. 1500
  14. 1400
  15. 1200
  16. 900
  17. 2400
  18. 600
  19. 400
  20. 6000
  21. 1200
  22. 1100
  23. 1000
  24. 900
  25. 1000
  26. 1800
  27. 2700
  28. 1400
  29. 4500
  30. 3200
  31. 1400
  32. 800
  33. 900
  34. 900
  35. 2800
  36. 1200
  37. 2500
  38. 1200
  39. 1000
  40. 700

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