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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 529 · 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 + … + 81 =
  2. 2.1 + 3 + 5 + … + 27 =
  3. 3.1 + 2 + 3 + … + 12 =
  4. 4.1 + 2 + 3 + … + 83 =
  5. 5.1 + 2 + 3 + … + 49 =
  6. 6.1 + 3 + 5 + … + 45 =
  7. 7.1 + 3 + 5 + … + 11 =
  8. 8.1 + 2 + 3 + … + 71 =
  9. 9.1 + 2 + 3 + … + 23 =
  10. 10.1 + 2 + 3 + … + 8 =
  11. 11.1 + 2 + 3 + … + 74 =
  12. 12.1 + 3 + 5 + … + 29 =
  13. 13.1 + 2 + 3 + … + 11 =
  14. 14.1 + 3 + 5 + … + 41 =
  15. 15.1 + 2 + 3 + … + 6 =
  16. 16.1 + 3 + 5 + … + 31 =
  17. 17.1 + 3 + 5 + … + 35 =
  18. 18.1 + 2 + 3 + … + 72 =
  19. 19.1 + 2 + 3 + … + 43 =
  20. 20.1 + 2 + 3 + … + 94 =
  21. 21.1 + 2 + 3 + … + 18 =
  22. 22.1 + 2 + 3 + … + 29 =
  23. 23.1 + 2 + 3 + … + 92 =
  24. 24.1 + 2 + 3 + … + 59 =
  25. 25.1 + 2 + 3 + … + 57 =
  26. 26.1 + 2 + 3 + … + 70 =
  27. 27.1 + 2 + 3 + … + 31 =
  28. 28.1 + 3 + 5 + … + 21 =
  29. 29.1 + 3 + 5 + … + 23 =
  30. 30.1 + 3 + 5 + … + 15 =
  31. 31.1 + 2 + 3 + … + 45 =
  32. 32.1 + 2 + 3 + … + 75 =
  33. 33.1 + 2 + 3 + … + 89 =
  34. 34.1 + 2 + 3 + … + 28 =
  35. 35.1 + 2 + 3 + … + 76 =
  36. 36.1 + 2 + 3 + … + 87 =
  37. 37.1 + 2 + 3 + … + 67 =
  38. 38.1 + 2 + 3 + … + 85 =
  39. 39.1 + 2 + 3 + … + 27 =
  40. 40.1 + 2 + 3 + … + 20 =

Answer key

  1. 3321
  2. 196
  3. 78
  4. 3486
  5. 1225
  6. 529
  7. 36
  8. 2556
  9. 276
  10. 36
  11. 2775
  12. 225
  13. 66
  14. 441
  15. 21
  16. 256
  17. 324
  18. 2628
  19. 946
  20. 4465
  21. 171
  22. 435
  23. 4278
  24. 1770
  25. 1653
  26. 2485
  27. 496
  28. 121
  29. 144
  30. 64
  31. 1035
  32. 2850
  33. 4005
  34. 406
  35. 2926
  36. 3828
  37. 2278
  38. 3655
  39. 378
  40. 210

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