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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 607 · 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 + … + 68 =
  2. 2.1 + 2 + 3 + … + 30 =
  3. 3.1 + 3 + 5 + … + 45 =
  4. 4.1 + 3 + 5 + … + 43 =
  5. 5.1 + 2 + 3 + … + 20 =
  6. 6.1 + 2 + 3 + … + 28 =
  7. 7.1 + 2 + 3 + … + 50 =
  8. 8.1 + 2 + 3 + … + 92 =
  9. 9.1 + 2 + 3 + … + 99 =
  10. 10.1 + 3 + 5 + … + 47 =
  11. 11.1 + 2 + 3 + … + 95 =
  12. 12.1 + 2 + 3 + … + 17 =
  13. 13.1 + 2 + 3 + … + 31 =
  14. 14.1 + 2 + 3 + … + 19 =
  15. 15.1 + 2 + 3 + … + 77 =
  16. 16.1 + 2 + 3 + … + 67 =
  17. 17.1 + 2 + 3 + … + 22 =
  18. 18.1 + 2 + 3 + … + 14 =
  19. 19.1 + 3 + 5 + … + 27 =
  20. 20.1 + 2 + 3 + … + 69 =
  21. 21.1 + 2 + 3 + … + 21 =
  22. 22.1 + 2 + 3 + … + 18 =
  23. 23.1 + 2 + 3 + … + 86 =
  24. 24.1 + 2 + 3 + … + 72 =
  25. 25.1 + 3 + 5 + … + 17 =
  26. 26.1 + 2 + 3 + … + 36 =
  27. 27.1 + 2 + 3 + … + 7 =
  28. 28.1 + 2 + 3 + … + 33 =
  29. 29.1 + 2 + 3 + … + 12 =
  30. 30.1 + 2 + 3 + … + 59 =
  31. 31.1 + 3 + 5 + … + 9 =
  32. 32.1 + 2 + 3 + … + 61 =
  33. 33.1 + 2 + 3 + … + 24 =
  34. 34.1 + 3 + 5 + … + 11 =
  35. 35.1 + 3 + 5 + … + 37 =
  36. 36.1 + 3 + 5 + … + 33 =
  37. 37.1 + 2 + 3 + … + 94 =
  38. 38.1 + 2 + 3 + … + 70 =
  39. 39.1 + 2 + 3 + … + 54 =
  40. 40.1 + 2 + 3 + … + 37 =

Answer key

  1. 2346
  2. 465
  3. 529
  4. 484
  5. 210
  6. 406
  7. 1275
  8. 4278
  9. 4950
  10. 576
  11. 4560
  12. 153
  13. 496
  14. 190
  15. 3003
  16. 2278
  17. 253
  18. 105
  19. 196
  20. 2415
  21. 231
  22. 171
  23. 3741
  24. 2628
  25. 81
  26. 666
  27. 28
  28. 561
  29. 78
  30. 1770
  31. 25
  32. 1891
  33. 300
  34. 36
  35. 361
  36. 289
  37. 4465
  38. 2485
  39. 1485
  40. 703

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