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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 111 · 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 + … + 60 =
  2. 2.1 + 2 + 3 + … + 52 =
  3. 3.1 + 2 + 3 + … + 97 =
  4. 4.1 + 3 + 5 + … + 43 =
  5. 5.1 + 3 + 5 + … + 21 =
  6. 6.1 + 2 + 3 + … + 73 =
  7. 7.1 + 3 + 5 + … + 15 =
  8. 8.1 + 2 + 3 + … + 11 =
  9. 9.1 + 2 + 3 + … + 50 =
  10. 10.1 + 2 + 3 + … + 56 =
  11. 11.1 + 2 + 3 + … + 88 =
  12. 12.1 + 3 + 5 + … + 23 =
  13. 13.1 + 2 + 3 + … + 20 =
  14. 14.1 + 3 + 5 + … + 41 =
  15. 15.1 + 2 + 3 + … + 100 =
  16. 16.1 + 2 + 3 + … + 69 =
  17. 17.1 + 3 + 5 + … + 39 =
  18. 18.1 + 2 + 3 + … + 93 =
  19. 19.1 + 2 + 3 + … + 21 =
  20. 20.1 + 3 + 5 + … + 45 =
  21. 21.1 + 2 + 3 + … + 84 =
  22. 22.1 + 2 + 3 + … + 33 =
  23. 23.1 + 2 + 3 + … + 14 =
  24. 24.1 + 3 + 5 + … + 29 =
  25. 25.1 + 2 + 3 + … + 67 =
  26. 26.1 + 3 + 5 + … + 9 =
  27. 27.1 + 2 + 3 + … + 28 =
  28. 28.1 + 2 + 3 + … + 68 =
  29. 29.1 + 3 + 5 + … + 11 =
  30. 30.1 + 2 + 3 + … + 25 =
  31. 31.1 + 2 + 3 + … + 94 =
  32. 32.1 + 2 + 3 + … + 63 =
  33. 33.1 + 2 + 3 + … + 86 =
  34. 34.1 + 2 + 3 + … + 54 =
  35. 35.1 + 2 + 3 + … + 83 =
  36. 36.1 + 3 + 5 + … + 25 =
  37. 37.1 + 3 + 5 + … + 27 =
  38. 38.1 + 2 + 3 + … + 70 =
  39. 39.1 + 2 + 3 + … + 26 =
  40. 40.1 + 2 + 3 + … + 80 =

Answer key

  1. 1830
  2. 1378
  3. 4753
  4. 484
  5. 121
  6. 2701
  7. 64
  8. 66
  9. 1275
  10. 1596
  11. 3916
  12. 144
  13. 210
  14. 441
  15. 5050
  16. 2415
  17. 400
  18. 4371
  19. 231
  20. 529
  21. 3570
  22. 561
  23. 105
  24. 225
  25. 2278
  26. 25
  27. 406
  28. 2346
  29. 36
  30. 325
  31. 4465
  32. 2016
  33. 3741
  34. 1485
  35. 3486
  36. 169
  37. 196
  38. 2485
  39. 351
  40. 3240

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