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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 670 · 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 + … + 29 =
  2. 2.1 + 2 + 3 + … + 92 =
  3. 3.1 + 3 + 5 + … + 43 =
  4. 4.1 + 3 + 5 + … + 15 =
  5. 5.1 + 3 + 5 + … + 13 =
  6. 6.1 + 2 + 3 + … + 27 =
  7. 7.1 + 2 + 3 + … + 95 =
  8. 8.1 + 2 + 3 + … + 57 =
  9. 9.1 + 2 + 3 + … + 71 =
  10. 10.1 + 3 + 5 + … + 9 =
  11. 11.1 + 3 + 5 + … + 23 =
  12. 12.1 + 3 + 5 + … + 17 =
  13. 13.1 + 2 + 3 + … + 19 =
  14. 14.1 + 2 + 3 + … + 9 =
  15. 15.1 + 2 + 3 + … + 87 =
  16. 16.1 + 2 + 3 + … + 45 =
  17. 17.1 + 3 + 5 + … + 49 =
  18. 18.1 + 2 + 3 + … + 33 =
  19. 19.1 + 2 + 3 + … + 30 =
  20. 20.1 + 3 + 5 + … + 31 =
  21. 21.1 + 2 + 3 + … + 97 =
  22. 22.1 + 2 + 3 + … + 94 =
  23. 23.1 + 2 + 3 + … + 22 =
  24. 24.1 + 3 + 5 + … + 41 =
  25. 25.1 + 3 + 5 + … + 27 =
  26. 26.1 + 3 + 5 + … + 35 =
  27. 27.1 + 2 + 3 + … + 13 =
  28. 28.1 + 2 + 3 + … + 69 =
  29. 29.1 + 2 + 3 + … + 70 =
  30. 30.1 + 2 + 3 + … + 28 =
  31. 31.1 + 2 + 3 + … + 88 =
  32. 32.1 + 2 + 3 + … + 14 =
  33. 33.1 + 2 + 3 + … + 72 =
  34. 34.1 + 3 + 5 + … + 37 =
  35. 35.1 + 3 + 5 + … + 11 =
  36. 36.1 + 2 + 3 + … + 61 =
  37. 37.1 + 3 + 5 + … + 19 =
  38. 38.1 + 2 + 3 + … + 8 =
  39. 39.1 + 2 + 3 + … + 20 =
  40. 40.1 + 2 + 3 + … + 7 =

Answer key

  1. 225
  2. 4278
  3. 484
  4. 64
  5. 49
  6. 378
  7. 4560
  8. 1653
  9. 2556
  10. 25
  11. 144
  12. 81
  13. 190
  14. 45
  15. 3828
  16. 1035
  17. 625
  18. 561
  19. 465
  20. 256
  21. 4753
  22. 4465
  23. 253
  24. 441
  25. 196
  26. 324
  27. 91
  28. 2415
  29. 2485
  30. 406
  31. 3916
  32. 105
  33. 2628
  34. 361
  35. 36
  36. 1891
  37. 100
  38. 36
  39. 210
  40. 28

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