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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 28 · 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 + … + 41 =
  2. 2.1 + 2 + 3 + … + 8 =
  3. 3.1 + 2 + 3 + … + 11 =
  4. 4.1 + 2 + 3 + … + 22 =
  5. 5.1 + 2 + 3 + … + 86 =
  6. 6.1 + 3 + 5 + … + 31 =
  7. 7.1 + 2 + 3 + … + 17 =
  8. 8.1 + 3 + 5 + … + 49 =
  9. 9.1 + 2 + 3 + … + 52 =
  10. 10.1 + 2 + 3 + … + 42 =
  11. 11.1 + 2 + 3 + … + 54 =
  12. 12.1 + 2 + 3 + … + 63 =
  13. 13.1 + 2 + 3 + … + 69 =
  14. 14.1 + 2 + 3 + … + 49 =
  15. 15.1 + 2 + 3 + … + 32 =
  16. 16.1 + 3 + 5 + … + 17 =
  17. 17.1 + 2 + 3 + … + 85 =
  18. 18.1 + 3 + 5 + … + 13 =
  19. 19.1 + 3 + 5 + … + 11 =
  20. 20.1 + 3 + 5 + … + 23 =
  21. 21.1 + 3 + 5 + … + 45 =
  22. 22.1 + 2 + 3 + … + 79 =
  23. 23.1 + 2 + 3 + … + 95 =
  24. 24.1 + 2 + 3 + … + 20 =
  25. 25.1 + 2 + 3 + … + 50 =
  26. 26.1 + 2 + 3 + … + 94 =
  27. 27.1 + 2 + 3 + … + 83 =
  28. 28.1 + 2 + 3 + … + 48 =
  29. 29.1 + 2 + 3 + … + 10 =
  30. 30.1 + 3 + 5 + … + 9 =
  31. 31.1 + 3 + 5 + … + 21 =
  32. 32.1 + 2 + 3 + … + 9 =
  33. 33.1 + 3 + 5 + … + 35 =
  34. 34.1 + 2 + 3 + … + 98 =
  35. 35.1 + 2 + 3 + … + 59 =
  36. 36.1 + 3 + 5 + … + 39 =
  37. 37.1 + 2 + 3 + … + 12 =
  38. 38.1 + 2 + 3 + … + 26 =
  39. 39.1 + 2 + 3 + … + 71 =
  40. 40.1 + 3 + 5 + … + 37 =

Answer key

  1. 441
  2. 36
  3. 66
  4. 253
  5. 3741
  6. 256
  7. 153
  8. 625
  9. 1378
  10. 903
  11. 1485
  12. 2016
  13. 2415
  14. 1225
  15. 528
  16. 81
  17. 3655
  18. 49
  19. 36
  20. 144
  21. 529
  22. 3160
  23. 4560
  24. 210
  25. 1275
  26. 4465
  27. 3486
  28. 1176
  29. 55
  30. 25
  31. 121
  32. 45
  33. 324
  34. 4851
  35. 1770
  36. 400
  37. 78
  38. 351
  39. 2556
  40. 361

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