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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 782 · 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 + … + 76 =
  2. 2.1 + 3 + 5 + … + 27 =
  3. 3.1 + 2 + 3 + … + 89 =
  4. 4.1 + 2 + 3 + … + 13 =
  5. 5.1 + 2 + 3 + … + 64 =
  6. 6.1 + 2 + 3 + … + 36 =
  7. 7.1 + 2 + 3 + … + 12 =
  8. 8.1 + 2 + 3 + … + 18 =
  9. 9.1 + 2 + 3 + … + 14 =
  10. 10.1 + 2 + 3 + … + 51 =
  11. 11.1 + 3 + 5 + … + 13 =
  12. 12.1 + 3 + 5 + … + 49 =
  13. 13.1 + 2 + 3 + … + 86 =
  14. 14.1 + 3 + 5 + … + 39 =
  15. 15.1 + 2 + 3 + … + 23 =
  16. 16.1 + 2 + 3 + … + 28 =
  17. 17.1 + 2 + 3 + … + 15 =
  18. 18.1 + 2 + 3 + … + 21 =
  19. 19.1 + 3 + 5 + … + 19 =
  20. 20.1 + 3 + 5 + … + 9 =
  21. 21.1 + 3 + 5 + … + 17 =
  22. 22.1 + 3 + 5 + … + 11 =
  23. 23.1 + 2 + 3 + … + 9 =
  24. 24.1 + 2 + 3 + … + 81 =
  25. 25.1 + 3 + 5 + … + 45 =
  26. 26.1 + 2 + 3 + … + 11 =
  27. 27.1 + 2 + 3 + … + 73 =
  28. 28.1 + 3 + 5 + … + 41 =
  29. 29.1 + 2 + 3 + … + 98 =
  30. 30.1 + 2 + 3 + … + 80 =
  31. 31.1 + 2 + 3 + … + 43 =
  32. 32.1 + 2 + 3 + … + 50 =
  33. 33.1 + 2 + 3 + … + 60 =
  34. 34.1 + 2 + 3 + … + 44 =
  35. 35.1 + 2 + 3 + … + 56 =
  36. 36.1 + 3 + 5 + … + 35 =
  37. 37.1 + 2 + 3 + … + 16 =
  38. 38.1 + 2 + 3 + … + 35 =
  39. 39.1 + 2 + 3 + … + 96 =
  40. 40.1 + 2 + 3 + … + 46 =

Answer key

  1. 2926
  2. 196
  3. 4005
  4. 91
  5. 2080
  6. 666
  7. 78
  8. 171
  9. 105
  10. 1326
  11. 49
  12. 625
  13. 3741
  14. 400
  15. 276
  16. 406
  17. 120
  18. 231
  19. 100
  20. 25
  21. 81
  22. 36
  23. 45
  24. 3321
  25. 529
  26. 66
  27. 2701
  28. 441
  29. 4851
  30. 3240
  31. 946
  32. 1275
  33. 1830
  34. 990
  35. 1596
  36. 324
  37. 136
  38. 630
  39. 4656
  40. 1081

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