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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 925 · 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 + … + 22 =
  2. 2.1 + 2 + 3 + … + 7 =
  3. 3.1 + 2 + 3 + … + 63 =
  4. 4.1 + 2 + 3 + … + 17 =
  5. 5.1 + 2 + 3 + … + 61 =
  6. 6.1 + 3 + 5 + … + 43 =
  7. 7.1 + 2 + 3 + … + 32 =
  8. 8.1 + 2 + 3 + … + 44 =
  9. 9.1 + 3 + 5 + … + 35 =
  10. 10.1 + 2 + 3 + … + 99 =
  11. 11.1 + 2 + 3 + … + 50 =
  12. 12.1 + 2 + 3 + … + 29 =
  13. 13.1 + 3 + 5 + … + 49 =
  14. 14.1 + 3 + 5 + … + 23 =
  15. 15.1 + 3 + 5 + … + 13 =
  16. 16.1 + 3 + 5 + … + 19 =
  17. 17.1 + 2 + 3 + … + 68 =
  18. 18.1 + 3 + 5 + … + 39 =
  19. 19.1 + 2 + 3 + … + 26 =
  20. 20.1 + 2 + 3 + … + 52 =
  21. 21.1 + 2 + 3 + … + 69 =
  22. 22.1 + 2 + 3 + … + 48 =
  23. 23.1 + 3 + 5 + … + 47 =
  24. 24.1 + 2 + 3 + … + 89 =
  25. 25.1 + 3 + 5 + … + 27 =
  26. 26.1 + 2 + 3 + … + 92 =
  27. 27.1 + 2 + 3 + … + 86 =
  28. 28.1 + 3 + 5 + … + 21 =
  29. 29.1 + 3 + 5 + … + 9 =
  30. 30.1 + 2 + 3 + … + 62 =
  31. 31.1 + 2 + 3 + … + 38 =
  32. 32.1 + 3 + 5 + … + 15 =
  33. 33.1 + 3 + 5 + … + 31 =
  34. 34.1 + 2 + 3 + … + 75 =
  35. 35.1 + 2 + 3 + … + 8 =
  36. 36.1 + 2 + 3 + … + 58 =
  37. 37.1 + 2 + 3 + … + 91 =
  38. 38.1 + 2 + 3 + … + 16 =
  39. 39.1 + 2 + 3 + … + 85 =
  40. 40.1 + 3 + 5 + … + 41 =

Answer key

  1. 253
  2. 28
  3. 2016
  4. 153
  5. 1891
  6. 484
  7. 528
  8. 990
  9. 324
  10. 4950
  11. 1275
  12. 435
  13. 625
  14. 144
  15. 49
  16. 100
  17. 2346
  18. 400
  19. 351
  20. 1378
  21. 2415
  22. 1176
  23. 576
  24. 4005
  25. 196
  26. 4278
  27. 3741
  28. 121
  29. 25
  30. 1953
  31. 741
  32. 64
  33. 256
  34. 2850
  35. 36
  36. 1711
  37. 4186
  38. 136
  39. 3655
  40. 441

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