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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 878 · 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 + 3 + 5 + … + 35 =
  2. 2.1 + 2 + 3 + … + 48 =
  3. 3.1 + 3 + 5 + … + 17 =
  4. 4.1 + 2 + 3 + … + 96 =
  5. 5.1 + 2 + 3 + … + 95 =
  6. 6.1 + 2 + 3 + … + 23 =
  7. 7.1 + 2 + 3 + … + 73 =
  8. 8.1 + 2 + 3 + … + 41 =
  9. 9.1 + 2 + 3 + … + 8 =
  10. 10.1 + 2 + 3 + … + 64 =
  11. 11.1 + 3 + 5 + … + 23 =
  12. 12.1 + 3 + 5 + … + 21 =
  13. 13.1 + 2 + 3 + … + 15 =
  14. 14.1 + 2 + 3 + … + 19 =
  15. 15.1 + 2 + 3 + … + 81 =
  16. 16.1 + 3 + 5 + … + 27 =
  17. 17.1 + 3 + 5 + … + 19 =
  18. 18.1 + 2 + 3 + … + 54 =
  19. 19.1 + 2 + 3 + … + 27 =
  20. 20.1 + 2 + 3 + … + 46 =
  21. 21.1 + 2 + 3 + … + 45 =
  22. 22.1 + 2 + 3 + … + 75 =
  23. 23.1 + 2 + 3 + … + 55 =
  24. 24.1 + 2 + 3 + … + 82 =
  25. 25.1 + 3 + 5 + … + 13 =
  26. 26.1 + 2 + 3 + … + 30 =
  27. 27.1 + 3 + 5 + … + 31 =
  28. 28.1 + 2 + 3 + … + 98 =
  29. 29.1 + 3 + 5 + … + 25 =
  30. 30.1 + 2 + 3 + … + 89 =
  31. 31.1 + 2 + 3 + … + 61 =
  32. 32.1 + 2 + 3 + … + 31 =
  33. 33.1 + 2 + 3 + … + 85 =
  34. 34.1 + 2 + 3 + … + 49 =
  35. 35.1 + 2 + 3 + … + 21 =
  36. 36.1 + 2 + 3 + … + 76 =
  37. 37.1 + 2 + 3 + … + 28 =
  38. 38.1 + 2 + 3 + … + 14 =
  39. 39.1 + 2 + 3 + … + 42 =
  40. 40.1 + 2 + 3 + … + 36 =

Answer key

  1. 324
  2. 1176
  3. 81
  4. 4656
  5. 4560
  6. 276
  7. 2701
  8. 861
  9. 36
  10. 2080
  11. 144
  12. 121
  13. 120
  14. 190
  15. 3321
  16. 196
  17. 100
  18. 1485
  19. 378
  20. 1081
  21. 1035
  22. 2850
  23. 1540
  24. 3403
  25. 49
  26. 465
  27. 256
  28. 4851
  29. 169
  30. 4005
  31. 1891
  32. 496
  33. 3655
  34. 1225
  35. 231
  36. 2926
  37. 406
  38. 105
  39. 903
  40. 666

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