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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 927 · 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 + 2 + 3 + … + 73 =
  2. 2.1 + 2 + 3 + … + 17 =
  3. 3.1 + 3 + 5 + … + 17 =
  4. 4.1 + 3 + 5 + … + 19 =
  5. 5.1 + 3 + 5 + … + 15 =
  6. 6.1 + 2 + 3 + … + 11 =
  7. 7.1 + 2 + 3 + … + 10 =
  8. 8.1 + 2 + 3 + … + 71 =
  9. 9.1 + 2 + 3 + … + 69 =
  10. 10.1 + 2 + 3 + … + 7 =
  11. 11.1 + 2 + 3 + … + 65 =
  12. 12.1 + 2 + 3 + … + 70 =
  13. 13.1 + 2 + 3 + … + 32 =
  14. 14.1 + 3 + 5 + … + 9 =
  15. 15.1 + 2 + 3 + … + 51 =
  16. 16.1 + 3 + 5 + … + 39 =
  17. 17.1 + 3 + 5 + … + 25 =
  18. 18.1 + 2 + 3 + … + 31 =
  19. 19.1 + 2 + 3 + … + 15 =
  20. 20.1 + 3 + 5 + … + 21 =
  21. 21.1 + 2 + 3 + … + 84 =
  22. 22.1 + 3 + 5 + … + 13 =
  23. 23.1 + 2 + 3 + … + 21 =
  24. 24.1 + 2 + 3 + … + 33 =
  25. 25.1 + 2 + 3 + … + 86 =
  26. 26.1 + 3 + 5 + … + 31 =
  27. 27.1 + 2 + 3 + … + 49 =
  28. 28.1 + 2 + 3 + … + 68 =
  29. 29.1 + 2 + 3 + … + 45 =
  30. 30.1 + 2 + 3 + … + 76 =
  31. 31.1 + 2 + 3 + … + 16 =
  32. 32.1 + 3 + 5 + … + 41 =
  33. 33.1 + 2 + 3 + … + 94 =
  34. 34.1 + 2 + 3 + … + 59 =
  35. 35.1 + 2 + 3 + … + 6 =
  36. 36.1 + 3 + 5 + … + 37 =
  37. 37.1 + 2 + 3 + … + 88 =
  38. 38.1 + 2 + 3 + … + 90 =
  39. 39.1 + 3 + 5 + … + 27 =
  40. 40.1 + 2 + 3 + … + 41 =

Answer key

  1. 2701
  2. 153
  3. 81
  4. 100
  5. 64
  6. 66
  7. 55
  8. 2556
  9. 2415
  10. 28
  11. 2145
  12. 2485
  13. 528
  14. 25
  15. 1326
  16. 400
  17. 169
  18. 496
  19. 120
  20. 121
  21. 3570
  22. 49
  23. 231
  24. 561
  25. 3741
  26. 256
  27. 1225
  28. 2346
  29. 1035
  30. 2926
  31. 136
  32. 441
  33. 4465
  34. 1770
  35. 21
  36. 361
  37. 3916
  38. 4095
  39. 196
  40. 861

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