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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 494 · 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 + … + 29 =
  2. 2.1 + 2 + 3 + … + 72 =
  3. 3.1 + 3 + 5 + … + 19 =
  4. 4.1 + 3 + 5 + … + 13 =
  5. 5.1 + 2 + 3 + … + 24 =
  6. 6.1 + 3 + 5 + … + 23 =
  7. 7.1 + 3 + 5 + … + 39 =
  8. 8.1 + 3 + 5 + … + 17 =
  9. 9.1 + 2 + 3 + … + 11 =
  10. 10.1 + 3 + 5 + … + 33 =
  11. 11.1 + 3 + 5 + … + 45 =
  12. 12.1 + 3 + 5 + … + 41 =
  13. 13.1 + 2 + 3 + … + 96 =
  14. 14.1 + 3 + 5 + … + 31 =
  15. 15.1 + 2 + 3 + … + 10 =
  16. 16.1 + 2 + 3 + … + 94 =
  17. 17.1 + 2 + 3 + … + 26 =
  18. 18.1 + 2 + 3 + … + 97 =
  19. 19.1 + 2 + 3 + … + 73 =
  20. 20.1 + 2 + 3 + … + 89 =
  21. 21.1 + 2 + 3 + … + 75 =
  22. 22.1 + 2 + 3 + … + 52 =
  23. 23.1 + 2 + 3 + … + 23 =
  24. 24.1 + 2 + 3 + … + 43 =
  25. 25.1 + 2 + 3 + … + 66 =
  26. 26.1 + 2 + 3 + … + 14 =
  27. 27.1 + 2 + 3 + … + 6 =
  28. 28.1 + 3 + 5 + … + 35 =
  29. 29.1 + 3 + 5 + … + 43 =
  30. 30.1 + 3 + 5 + … + 27 =
  31. 31.1 + 2 + 3 + … + 76 =
  32. 32.1 + 2 + 3 + … + 17 =
  33. 33.1 + 2 + 3 + … + 65 =
  34. 34.1 + 2 + 3 + … + 54 =
  35. 35.1 + 2 + 3 + … + 25 =
  36. 36.1 + 3 + 5 + … + 15 =
  37. 37.1 + 2 + 3 + … + 79 =
  38. 38.1 + 2 + 3 + … + 63 =
  39. 39.1 + 2 + 3 + … + 92 =
  40. 40.1 + 2 + 3 + … + 31 =

Answer key

  1. 225
  2. 2628
  3. 100
  4. 49
  5. 300
  6. 144
  7. 400
  8. 81
  9. 66
  10. 289
  11. 529
  12. 441
  13. 4656
  14. 256
  15. 55
  16. 4465
  17. 351
  18. 4753
  19. 2701
  20. 4005
  21. 2850
  22. 1378
  23. 276
  24. 946
  25. 2211
  26. 105
  27. 21
  28. 324
  29. 484
  30. 196
  31. 2926
  32. 153
  33. 2145
  34. 1485
  35. 325
  36. 64
  37. 3160
  38. 2016
  39. 4278
  40. 496

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