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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 246 · 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 + … + 18 =
  2. 2.1 + 3 + 5 + … + 33 =
  3. 3.1 + 2 + 3 + … + 32 =
  4. 4.1 + 2 + 3 + … + 9 =
  5. 5.1 + 3 + 5 + … + 17 =
  6. 6.1 + 2 + 3 + … + 74 =
  7. 7.1 + 2 + 3 + … + 97 =
  8. 8.1 + 2 + 3 + … + 23 =
  9. 9.1 + 2 + 3 + … + 81 =
  10. 10.1 + 2 + 3 + … + 13 =
  11. 11.1 + 2 + 3 + … + 15 =
  12. 12.1 + 2 + 3 + … + 44 =
  13. 13.1 + 2 + 3 + … + 63 =
  14. 14.1 + 2 + 3 + … + 82 =
  15. 15.1 + 2 + 3 + … + 75 =
  16. 16.1 + 3 + 5 + … + 13 =
  17. 17.1 + 3 + 5 + … + 21 =
  18. 18.1 + 2 + 3 + … + 41 =
  19. 19.1 + 2 + 3 + … + 43 =
  20. 20.1 + 2 + 3 + … + 22 =
  21. 21.1 + 3 + 5 + … + 45 =
  22. 22.1 + 3 + 5 + … + 11 =
  23. 23.1 + 3 + 5 + … + 27 =
  24. 24.1 + 2 + 3 + … + 85 =
  25. 25.1 + 3 + 5 + … + 25 =
  26. 26.1 + 2 + 3 + … + 83 =
  27. 27.1 + 2 + 3 + … + 72 =
  28. 28.1 + 2 + 3 + … + 76 =
  29. 29.1 + 3 + 5 + … + 19 =
  30. 30.1 + 2 + 3 + … + 21 =
  31. 31.1 + 2 + 3 + … + 16 =
  32. 32.1 + 2 + 3 + … + 68 =
  33. 33.1 + 2 + 3 + … + 8 =
  34. 34.1 + 2 + 3 + … + 73 =
  35. 35.1 + 2 + 3 + … + 51 =
  36. 36.1 + 2 + 3 + … + 58 =
  37. 37.1 + 2 + 3 + … + 78 =
  38. 38.1 + 3 + 5 + … + 15 =
  39. 39.1 + 2 + 3 + … + 42 =
  40. 40.1 + 2 + 3 + … + 31 =

Answer key

  1. 171
  2. 289
  3. 528
  4. 45
  5. 81
  6. 2775
  7. 4753
  8. 276
  9. 3321
  10. 91
  11. 120
  12. 990
  13. 2016
  14. 3403
  15. 2850
  16. 49
  17. 121
  18. 861
  19. 946
  20. 253
  21. 529
  22. 36
  23. 196
  24. 3655
  25. 169
  26. 3486
  27. 2628
  28. 2926
  29. 100
  30. 231
  31. 136
  32. 2346
  33. 36
  34. 2701
  35. 1326
  36. 1711
  37. 3081
  38. 64
  39. 903
  40. 496

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