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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 974 · 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 426 + 720? (a) 1300 (b) 1100 (c) 900
  2. 2.Best estimate of 92 × 89? (a) 810 (b) 81000 (c) 8100
  3. 3.Best estimate of 26 × 13? (a) 300 (b) 30 (c) 3000
  4. 4.Best estimate of 53 × 38? (a) 2000 (b) 200 (c) 20000
  5. 5.Best estimate of 752 + 699? (a) 1500 (b) 1700 (c) 1300
  6. 6.Best estimate of 80 × 36? (a) 32000 (b) 3200 (c) 320
  7. 7.Best estimate of 36 × 96? (a) 400 (b) 40000 (c) 4000
  8. 8.Best estimate of 87 × 66? (a) 630 (b) 6300 (c) 63000
  9. 9.Best estimate of 22 × 64? (a) 12000 (b) 1200 (c) 120
  10. 10.Best estimate of 617 + 214? (a) 800 (b) 600 (c) 1000
  11. 11.Best estimate of 143 + 612? (a) 900 (b) 700 (c) 500
  12. 12.Best estimate of 183 + 878? (a) 900 (b) 1100 (c) 1300
  13. 13.Best estimate of 29 × 84? (a) 2400 (b) 240 (c) 24000
  14. 14.Best estimate of 606 + 613? (a) 1200 (b) 1000 (c) 1400
  15. 15.Best estimate of 139 + 602? (a) 700 (b) 500 (c) 900
  16. 16.Best estimate of 84 × 69? (a) 560 (b) 56000 (c) 5600
  17. 17.Best estimate of 251 + 432? (a) 700 (b) 900 (c) 500
  18. 18.Best estimate of 508 + 684? (a) 1400 (b) 1200 (c) 1000
  19. 19.Best estimate of 76 × 16? (a) 1600 (b) 160 (c) 16000
  20. 20.Best estimate of 857 + 410? (a) 1500 (b) 1100 (c) 1300
  21. 21.Best estimate of 225 + 271? (a) 500 (b) 300 (c) 700
  22. 22.Best estimate of 19 × 76? (a) 16000 (b) 1600 (c) 160
  23. 23.Best estimate of 875 + 860? (a) 2000 (b) 1800 (c) 1600
  24. 24.Best estimate of 83 × 90? (a) 720 (b) 7200 (c) 72000
  25. 25.Best estimate of 36 × 37? (a) 16000 (b) 160 (c) 1600
  26. 26.Best estimate of 406 + 265? (a) 500 (b) 700 (c) 900
  27. 27.Best estimate of 93 × 87? (a) 8100 (b) 81000 (c) 810
  28. 28.Best estimate of 16 × 26? (a) 6000 (b) 60 (c) 600
  29. 29.Best estimate of 585 + 246? (a) 600 (b) 800 (c) 1000
  30. 30.Best estimate of 14 × 13? (a) 1000 (b) 10 (c) 100
  31. 31.Best estimate of 257 + 589? (a) 900 (b) 700 (c) 1100
  32. 32.Best estimate of 82 × 62? (a) 4800 (b) 48000 (c) 480
  33. 33.Best estimate of 517 + 551? (a) 1300 (b) 900 (c) 1100
  34. 34.Best estimate of 139 + 483? (a) 600 (b) 400 (c) 800
  35. 35.Best estimate of 46 × 37? (a) 2000 (b) 20000 (c) 200
  36. 36.Best estimate of 89 × 19? (a) 180 (b) 18000 (c) 1800
  37. 37.Best estimate of 241 + 632? (a) 1000 (b) 800 (c) 600
  38. 38.Best estimate of 43 × 68? (a) 28000 (b) 2800 (c) 280
  39. 39.Best estimate of 209 + 874? (a) 900 (b) 1100 (c) 1300
  40. 40.Best estimate of 81 × 42? (a) 320 (b) 32000 (c) 3200

Answer key

  1. 1100
  2. 8100
  3. 300
  4. 2000
  5. 1500
  6. 3200
  7. 4000
  8. 6300
  9. 1200
  10. 800
  11. 700
  12. 1100
  13. 2400
  14. 1200
  15. 700
  16. 5600
  17. 700
  18. 1200
  19. 1600
  20. 1300
  21. 500
  22. 1600
  23. 1800
  24. 7200
  25. 1600
  26. 700
  27. 8100
  28. 600
  29. 800
  30. 100
  31. 900
  32. 4800
  33. 1100
  34. 600
  35. 2000
  36. 1800
  37. 800
  38. 2800
  39. 1100
  40. 3200

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