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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 108 · 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 + … + 45 =
  2. 2.1 + 2 + 3 + … + 48 =
  3. 3.1 + 2 + 3 + … + 19 =
  4. 4.1 + 2 + 3 + … + 93 =
  5. 5.1 + 2 + 3 + … + 80 =
  6. 6.1 + 3 + 5 + … + 39 =
  7. 7.1 + 3 + 5 + … + 27 =
  8. 8.1 + 2 + 3 + … + 31 =
  9. 9.1 + 2 + 3 + … + 46 =
  10. 10.1 + 2 + 3 + … + 53 =
  11. 11.1 + 2 + 3 + … + 63 =
  12. 12.1 + 3 + 5 + … + 17 =
  13. 13.1 + 2 + 3 + … + 69 =
  14. 14.1 + 2 + 3 + … + 58 =
  15. 15.1 + 2 + 3 + … + 86 =
  16. 16.1 + 2 + 3 + … + 76 =
  17. 17.1 + 2 + 3 + … + 36 =
  18. 18.1 + 3 + 5 + … + 23 =
  19. 19.1 + 3 + 5 + … + 15 =
  20. 20.1 + 2 + 3 + … + 68 =
  21. 21.1 + 3 + 5 + … + 41 =
  22. 22.1 + 3 + 5 + … + 13 =
  23. 23.1 + 2 + 3 + … + 91 =
  24. 24.1 + 3 + 5 + … + 43 =
  25. 25.1 + 2 + 3 + … + 62 =
  26. 26.1 + 2 + 3 + … + 51 =
  27. 27.1 + 2 + 3 + … + 75 =
  28. 28.1 + 2 + 3 + … + 27 =
  29. 29.1 + 2 + 3 + … + 66 =
  30. 30.1 + 3 + 5 + … + 31 =
  31. 31.1 + 3 + 5 + … + 29 =
  32. 32.1 + 2 + 3 + … + 13 =
  33. 33.1 + 3 + 5 + … + 49 =
  34. 34.1 + 3 + 5 + … + 47 =
  35. 35.1 + 2 + 3 + … + 71 =
  36. 36.1 + 3 + 5 + … + 25 =
  37. 37.1 + 2 + 3 + … + 84 =
  38. 38.1 + 2 + 3 + … + 94 =
  39. 39.1 + 2 + 3 + … + 11 =
  40. 40.1 + 2 + 3 + … + 24 =

Answer key

  1. 529
  2. 1176
  3. 190
  4. 4371
  5. 3240
  6. 400
  7. 196
  8. 496
  9. 1081
  10. 1431
  11. 2016
  12. 81
  13. 2415
  14. 1711
  15. 3741
  16. 2926
  17. 666
  18. 144
  19. 64
  20. 2346
  21. 441
  22. 49
  23. 4186
  24. 484
  25. 1953
  26. 1326
  27. 2850
  28. 378
  29. 2211
  30. 256
  31. 225
  32. 91
  33. 625
  34. 576
  35. 2556
  36. 169
  37. 3570
  38. 4465
  39. 66
  40. 300

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