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Rounding Off and Estimation Worksheet

Mental maths lesson 15: Rounding off and best estimate · Set 841 · 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 54 × 13? (a) 50 (b) 5000 (c) 500
  2. 2.Best estimate of 697 + 503? (a) 1000 (b) 1400 (c) 1200
  3. 3.Best estimate of 37 × 28? (a) 12000 (b) 1200 (c) 120
  4. 4.Best estimate of 143 + 258? (a) 400 (b) 600 (c) 200
  5. 5.Best estimate of 302 + 836? (a) 1100 (b) 900 (c) 1300
  6. 6.Best estimate of 47 × 66? (a) 350 (b) 35000 (c) 3500
  7. 7.Best estimate of 58 × 16? (a) 1200 (b) 12000 (c) 120
  8. 8.Best estimate of 31 × 88? (a) 2700 (b) 270 (c) 27000
  9. 9.Best estimate of 828 + 374? (a) 1400 (b) 1200 (c) 1000
  10. 10.Best estimate of 31 × 33? (a) 9000 (b) 90 (c) 900
  11. 11.Best estimate of 296 + 305? (a) 800 (b) 600 (c) 400
  12. 12.Best estimate of 57 × 28? (a) 1800 (b) 18000 (c) 180
  13. 13.Best estimate of 486 + 455? (a) 1000 (b) 800 (c) 1200
  14. 14.Best estimate of 39 × 56? (a) 2400 (b) 240 (c) 24000
  15. 15.Best estimate of 53 × 53? (a) 25000 (b) 250 (c) 2500
  16. 16.Best estimate of 98 × 60? (a) 600 (b) 6000 (c) 60000
  17. 17.Best estimate of 630 + 716? (a) 1100 (b) 1300 (c) 1500
  18. 18.Best estimate of 82 × 86? (a) 7200 (b) 72000 (c) 720
  19. 19.Best estimate of 164 + 339? (a) 700 (b) 300 (c) 500
  20. 20.Best estimate of 58 × 47? (a) 3000 (b) 300 (c) 30000
  21. 21.Best estimate of 773 + 297? (a) 900 (b) 1100 (c) 1300
  22. 22.Best estimate of 21 × 16? (a) 400 (b) 40 (c) 4000
  23. 23.Best estimate of 41 × 14? (a) 400 (b) 40 (c) 4000
  24. 24.Best estimate of 77 × 26? (a) 240 (b) 24000 (c) 2400
  25. 25.Best estimate of 696 + 811? (a) 1500 (b) 1700 (c) 1300
  26. 26.Best estimate of 70 × 32? (a) 21000 (b) 210 (c) 2100
  27. 27.Best estimate of 309 + 227? (a) 300 (b) 700 (c) 500
  28. 28.Best estimate of 723 + 869? (a) 1600 (b) 1800 (c) 1400
  29. 29.Best estimate of 797 + 298? (a) 900 (b) 1300 (c) 1100
  30. 30.Best estimate of 318 + 482? (a) 1000 (b) 600 (c) 800
  31. 31.Best estimate of 736 + 605? (a) 1500 (b) 1100 (c) 1300
  32. 32.Best estimate of 34 × 28? (a) 90 (b) 900 (c) 9000
  33. 33.Best estimate of 537 + 693? (a) 1200 (b) 1400 (c) 1000
  34. 34.Best estimate of 71 × 86? (a) 6300 (b) 63000 (c) 630
  35. 35.Best estimate of 68 × 59? (a) 42000 (b) 4200 (c) 420
  36. 36.Best estimate of 838 + 507? (a) 1100 (b) 1300 (c) 1500
  37. 37.Best estimate of 759 + 540? (a) 1300 (b) 1100 (c) 1500
  38. 38.Best estimate of 319 + 424? (a) 900 (b) 700 (c) 500
  39. 39.Best estimate of 51 × 62? (a) 3000 (b) 300 (c) 30000
  40. 40.Best estimate of 78 × 73? (a) 5600 (b) 560 (c) 56000

Answer key

  1. 500
  2. 1200
  3. 1200
  4. 400
  5. 1100
  6. 3500
  7. 1200
  8. 2700
  9. 1200
  10. 900
  11. 600
  12. 1800
  13. 1000
  14. 2400
  15. 2500
  16. 6000
  17. 1300
  18. 7200
  19. 500
  20. 3000
  21. 1100
  22. 400
  23. 400
  24. 2400
  25. 1500
  26. 2100
  27. 500
  28. 1600
  29. 1100
  30. 800
  31. 1300
  32. 900
  33. 1200
  34. 6300
  35. 4200
  36. 1300
  37. 1300
  38. 700
  39. 3000
  40. 5600

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