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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 527 · 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 + … + 31 =
  2. 2.1 + 2 + 3 + … + 61 =
  3. 3.1 + 2 + 3 + … + 22 =
  4. 4.1 + 2 + 3 + … + 27 =
  5. 5.1 + 2 + 3 + … + 57 =
  6. 6.1 + 2 + 3 + … + 53 =
  7. 7.1 + 2 + 3 + … + 97 =
  8. 8.1 + 2 + 3 + … + 95 =
  9. 9.1 + 2 + 3 + … + 17 =
  10. 10.1 + 2 + 3 + … + 23 =
  11. 11.1 + 2 + 3 + … + 78 =
  12. 12.1 + 2 + 3 + … + 94 =
  13. 13.1 + 2 + 3 + … + 80 =
  14. 14.1 + 3 + 5 + … + 43 =
  15. 15.1 + 2 + 3 + … + 38 =
  16. 16.1 + 2 + 3 + … + 10 =
  17. 17.1 + 2 + 3 + … + 30 =
  18. 18.1 + 2 + 3 + … + 28 =
  19. 19.1 + 3 + 5 + … + 23 =
  20. 20.1 + 3 + 5 + … + 19 =
  21. 21.1 + 3 + 5 + … + 9 =
  22. 22.1 + 3 + 5 + … + 27 =
  23. 23.1 + 3 + 5 + … + 49 =
  24. 24.1 + 2 + 3 + … + 15 =
  25. 25.1 + 3 + 5 + … + 17 =
  26. 26.1 + 2 + 3 + … + 59 =
  27. 27.1 + 2 + 3 + … + 24 =
  28. 28.1 + 3 + 5 + … + 13 =
  29. 29.1 + 3 + 5 + … + 29 =
  30. 30.1 + 2 + 3 + … + 13 =
  31. 31.1 + 2 + 3 + … + 71 =
  32. 32.1 + 3 + 5 + … + 25 =
  33. 33.1 + 2 + 3 + … + 50 =
  34. 34.1 + 2 + 3 + … + 67 =
  35. 35.1 + 2 + 3 + … + 92 =
  36. 36.1 + 3 + 5 + … + 47 =
  37. 37.1 + 2 + 3 + … + 18 =
  38. 38.1 + 2 + 3 + … + 68 =
  39. 39.1 + 2 + 3 + … + 66 =
  40. 40.1 + 2 + 3 + … + 73 =

Answer key

  1. 256
  2. 1891
  3. 253
  4. 378
  5. 1653
  6. 1431
  7. 4753
  8. 4560
  9. 153
  10. 276
  11. 3081
  12. 4465
  13. 3240
  14. 484
  15. 741
  16. 55
  17. 465
  18. 406
  19. 144
  20. 100
  21. 25
  22. 196
  23. 625
  24. 120
  25. 81
  26. 1770
  27. 300
  28. 49
  29. 225
  30. 91
  31. 2556
  32. 169
  33. 1275
  34. 2278
  35. 4278
  36. 576
  37. 171
  38. 2346
  39. 2211
  40. 2701

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