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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 822 · 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 760 + 281? (a) 1300 (b) 1100 (c) 900
  2. 2.Best estimate of 547 + 427? (a) 700 (b) 900 (c) 1100
  3. 3.Best estimate of 374 + 234? (a) 800 (b) 600 (c) 400
  4. 4.Best estimate of 46 × 96? (a) 50000 (b) 500 (c) 5000
  5. 5.Best estimate of 14 × 82? (a) 8000 (b) 80 (c) 800
  6. 6.Best estimate of 127 + 406? (a) 300 (b) 700 (c) 500
  7. 7.Best estimate of 56 × 60? (a) 360 (b) 3600 (c) 36000
  8. 8.Best estimate of 846 + 479? (a) 1100 (b) 1500 (c) 1300
  9. 9.Best estimate of 239 + 780? (a) 1000 (b) 800 (c) 1200
  10. 10.Best estimate of 33 × 98? (a) 3000 (b) 300 (c) 30000
  11. 11.Best estimate of 281 + 293? (a) 600 (b) 400 (c) 800
  12. 12.Best estimate of 836 + 153? (a) 1000 (b) 1200 (c) 800
  13. 13.Best estimate of 664 + 183? (a) 700 (b) 900 (c) 1100
  14. 14.Best estimate of 30 × 16? (a) 60 (b) 6000 (c) 600
  15. 15.Best estimate of 69 × 69? (a) 49000 (b) 4900 (c) 490
  16. 16.Best estimate of 83 × 42? (a) 320 (b) 32000 (c) 3200
  17. 17.Best estimate of 628 + 360? (a) 1000 (b) 1200 (c) 800
  18. 18.Best estimate of 22 × 76? (a) 16000 (b) 1600 (c) 160
  19. 19.Best estimate of 816 + 367? (a) 1400 (b) 1200 (c) 1000
  20. 20.Best estimate of 84 × 16? (a) 160 (b) 1600 (c) 16000
  21. 21.Best estimate of 44 × 76? (a) 32000 (b) 320 (c) 3200
  22. 22.Best estimate of 511 + 124? (a) 400 (b) 600 (c) 800
  23. 23.Best estimate of 359 + 733? (a) 1100 (b) 900 (c) 1300
  24. 24.Best estimate of 164 + 386? (a) 800 (b) 600 (c) 400
  25. 25.Best estimate of 714 + 682? (a) 1600 (b) 1400 (c) 1200
  26. 26.Best estimate of 36 × 80? (a) 3200 (b) 32000 (c) 320
  27. 27.Best estimate of 521 + 417? (a) 1100 (b) 900 (c) 700
  28. 28.Best estimate of 206 + 525? (a) 500 (b) 900 (c) 700
  29. 29.Best estimate of 28 × 83? (a) 240 (b) 2400 (c) 24000
  30. 30.Best estimate of 14 × 48? (a) 500 (b) 5000 (c) 50
  31. 31.Best estimate of 299 + 856? (a) 1400 (b) 1200 (c) 1000
  32. 32.Best estimate of 26 × 54? (a) 15000 (b) 150 (c) 1500
  33. 33.Best estimate of 72 × 16? (a) 1400 (b) 14000 (c) 140
  34. 34.Best estimate of 12 × 18? (a) 20 (b) 200 (c) 2000
  35. 35.Best estimate of 757 + 590? (a) 1400 (b) 1600 (c) 1200
  36. 36.Best estimate of 39 × 36? (a) 160 (b) 1600 (c) 16000
  37. 37.Best estimate of 479 + 710? (a) 1400 (b) 1000 (c) 1200
  38. 38.Best estimate of 28 × 50? (a) 1500 (b) 15000 (c) 150
  39. 39.Best estimate of 668 + 444? (a) 900 (b) 1100 (c) 1300
  40. 40.Best estimate of 57 × 72? (a) 420 (b) 42000 (c) 4200

Answer key

  1. 1100
  2. 900
  3. 600
  4. 5000
  5. 800
  6. 500
  7. 3600
  8. 1300
  9. 1000
  10. 3000
  11. 600
  12. 1000
  13. 900
  14. 600
  15. 4900
  16. 3200
  17. 1000
  18. 1600
  19. 1200
  20. 1600
  21. 3200
  22. 600
  23. 1100
  24. 600
  25. 1400
  26. 3200
  27. 900
  28. 700
  29. 2400
  30. 500
  31. 1200
  32. 1500
  33. 1400
  34. 200
  35. 1400
  36. 1600
  37. 1200
  38. 1500
  39. 1100
  40. 4200

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