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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 536 · 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 + … + 33 =
  2. 2.1 + 2 + 3 + … + 48 =
  3. 3.1 + 3 + 5 + … + 29 =
  4. 4.1 + 2 + 3 + … + 97 =
  5. 5.1 + 2 + 3 + … + 32 =
  6. 6.1 + 2 + 3 + … + 20 =
  7. 7.1 + 2 + 3 + … + 53 =
  8. 8.1 + 2 + 3 + … + 9 =
  9. 9.1 + 3 + 5 + … + 33 =
  10. 10.1 + 2 + 3 + … + 56 =
  11. 11.1 + 2 + 3 + … + 40 =
  12. 12.1 + 2 + 3 + … + 36 =
  13. 13.1 + 3 + 5 + … + 43 =
  14. 14.1 + 3 + 5 + … + 35 =
  15. 15.1 + 3 + 5 + … + 11 =
  16. 16.1 + 2 + 3 + … + 28 =
  17. 17.1 + 3 + 5 + … + 27 =
  18. 18.1 + 2 + 3 + … + 51 =
  19. 19.1 + 2 + 3 + … + 88 =
  20. 20.1 + 2 + 3 + … + 98 =
  21. 21.1 + 3 + 5 + … + 45 =
  22. 22.1 + 2 + 3 + … + 49 =
  23. 23.1 + 3 + 5 + … + 9 =
  24. 24.1 + 2 + 3 + … + 26 =
  25. 25.1 + 2 + 3 + … + 79 =
  26. 26.1 + 2 + 3 + … + 76 =
  27. 27.1 + 2 + 3 + … + 44 =
  28. 28.1 + 2 + 3 + … + 8 =
  29. 29.1 + 2 + 3 + … + 19 =
  30. 30.1 + 2 + 3 + … + 46 =
  31. 31.1 + 2 + 3 + … + 70 =
  32. 32.1 + 2 + 3 + … + 77 =
  33. 33.1 + 2 + 3 + … + 69 =
  34. 34.1 + 3 + 5 + … + 19 =
  35. 35.1 + 2 + 3 + … + 50 =
  36. 36.1 + 2 + 3 + … + 23 =
  37. 37.1 + 2 + 3 + … + 55 =
  38. 38.1 + 2 + 3 + … + 35 =
  39. 39.1 + 2 + 3 + … + 75 =
  40. 40.1 + 3 + 5 + … + 21 =

Answer key

  1. 561
  2. 1176
  3. 225
  4. 4753
  5. 528
  6. 210
  7. 1431
  8. 45
  9. 289
  10. 1596
  11. 820
  12. 666
  13. 484
  14. 324
  15. 36
  16. 406
  17. 196
  18. 1326
  19. 3916
  20. 4851
  21. 529
  22. 1225
  23. 25
  24. 351
  25. 3160
  26. 2926
  27. 990
  28. 36
  29. 190
  30. 1081
  31. 2485
  32. 3003
  33. 2415
  34. 100
  35. 1275
  36. 276
  37. 1540
  38. 630
  39. 2850
  40. 121

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