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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 29 · 40 questions
TalentJR

The trick (Pairs): Pair the first and last numbers: each pair adds to n + 1. Count the pairs — or multiply n × (n + 1) and halve it. Odd numbers 1 + 3 + 5 + …: count them and multiply that count by itself.

NameDateTime takenScore ___ / 40
  1. 1.1 + 3 + 5 + … + 47 =
  2. 2.1 + 3 + 5 + … + 45 =
  3. 3.1 + 2 + 3 + … + 46 =
  4. 4.1 + 2 + 3 + … + 66 =
  5. 5.1 + 2 + 3 + … + 80 =
  6. 6.1 + 2 + 3 + … + 11 =
  7. 7.1 + 2 + 3 + … + 56 =
  8. 8.1 + 2 + 3 + … + 6 =
  9. 9.1 + 3 + 5 + … + 13 =
  10. 10.1 + 2 + 3 + … + 97 =
  11. 11.1 + 2 + 3 + … + 98 =
  12. 12.1 + 2 + 3 + … + 63 =
  13. 13.1 + 2 + 3 + … + 99 =
  14. 14.1 + 2 + 3 + … + 33 =
  15. 15.1 + 3 + 5 + … + 23 =
  16. 16.1 + 2 + 3 + … + 14 =
  17. 17.1 + 2 + 3 + … + 35 =
  18. 18.1 + 2 + 3 + … + 12 =
  19. 19.1 + 2 + 3 + … + 84 =
  20. 20.1 + 2 + 3 + … + 29 =
  21. 21.1 + 2 + 3 + … + 43 =
  22. 22.1 + 2 + 3 + … + 27 =
  23. 23.1 + 2 + 3 + … + 53 =
  24. 24.1 + 2 + 3 + … + 62 =
  25. 25.1 + 3 + 5 + … + 15 =
  26. 26.1 + 2 + 3 + … + 75 =
  27. 27.1 + 2 + 3 + … + 55 =
  28. 28.1 + 2 + 3 + … + 30 =
  29. 29.1 + 3 + 5 + … + 11 =
  30. 30.1 + 2 + 3 + … + 45 =
  31. 31.1 + 2 + 3 + … + 41 =
  32. 32.1 + 2 + 3 + … + 13 =
  33. 33.1 + 2 + 3 + … + 71 =
  34. 34.1 + 2 + 3 + … + 44 =
  35. 35.1 + 2 + 3 + … + 23 =
  36. 36.1 + 2 + 3 + … + 39 =
  37. 37.1 + 3 + 5 + … + 43 =
  38. 38.1 + 2 + 3 + … + 82 =
  39. 39.1 + 3 + 5 + … + 31 =
  40. 40.1 + 3 + 5 + … + 27 =

Answer key

  1. 576
  2. 529
  3. 1081
  4. 2211
  5. 3240
  6. 66
  7. 1596
  8. 21
  9. 49
  10. 4753
  11. 4851
  12. 2016
  13. 4950
  14. 561
  15. 144
  16. 105
  17. 630
  18. 78
  19. 3570
  20. 435
  21. 946
  22. 378
  23. 1431
  24. 1953
  25. 64
  26. 2850
  27. 1540
  28. 465
  29. 36
  30. 1035
  31. 861
  32. 91
  33. 2556
  34. 990
  35. 276
  36. 780
  37. 484
  38. 3403
  39. 256
  40. 196

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