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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 253 · 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 + … + 73 =
  3. 3.1 + 2 + 3 + … + 92 =
  4. 4.1 + 3 + 5 + … + 41 =
  5. 5.1 + 2 + 3 + … + 38 =
  6. 6.1 + 2 + 3 + … + 50 =
  7. 7.1 + 2 + 3 + … + 9 =
  8. 8.1 + 2 + 3 + … + 78 =
  9. 9.1 + 2 + 3 + … + 49 =
  10. 10.1 + 3 + 5 + … + 31 =
  11. 11.1 + 2 + 3 + … + 75 =
  12. 12.1 + 2 + 3 + … + 19 =
  13. 13.1 + 2 + 3 + … + 23 =
  14. 14.1 + 2 + 3 + … + 32 =
  15. 15.1 + 3 + 5 + … + 33 =
  16. 16.1 + 3 + 5 + … + 11 =
  17. 17.1 + 2 + 3 + … + 48 =
  18. 18.1 + 2 + 3 + … + 30 =
  19. 19.1 + 3 + 5 + … + 25 =
  20. 20.1 + 2 + 3 + … + 54 =
  21. 21.1 + 3 + 5 + … + 49 =
  22. 22.1 + 3 + 5 + … + 15 =
  23. 23.1 + 2 + 3 + … + 66 =
  24. 24.1 + 2 + 3 + … + 74 =
  25. 25.1 + 2 + 3 + … + 31 =
  26. 26.1 + 3 + 5 + … + 21 =
  27. 27.1 + 2 + 3 + … + 27 =
  28. 28.1 + 2 + 3 + … + 64 =
  29. 29.1 + 3 + 5 + … + 45 =
  30. 30.1 + 2 + 3 + … + 97 =
  31. 31.1 + 2 + 3 + … + 71 =
  32. 32.1 + 2 + 3 + … + 36 =
  33. 33.1 + 2 + 3 + … + 86 =
  34. 34.1 + 2 + 3 + … + 13 =
  35. 35.1 + 2 + 3 + … + 42 =
  36. 36.1 + 2 + 3 + … + 8 =
  37. 37.1 + 2 + 3 + … + 61 =
  38. 38.1 + 3 + 5 + … + 17 =
  39. 39.1 + 2 + 3 + … + 85 =
  40. 40.1 + 3 + 5 + … + 13 =

Answer key

  1. 561
  2. 2701
  3. 4278
  4. 441
  5. 741
  6. 1275
  7. 45
  8. 3081
  9. 1225
  10. 256
  11. 2850
  12. 190
  13. 276
  14. 528
  15. 289
  16. 36
  17. 1176
  18. 465
  19. 169
  20. 1485
  21. 625
  22. 64
  23. 2211
  24. 2775
  25. 496
  26. 121
  27. 378
  28. 2080
  29. 529
  30. 4753
  31. 2556
  32. 666
  33. 3741
  34. 91
  35. 903
  36. 36
  37. 1891
  38. 81
  39. 3655
  40. 49

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