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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 65 · 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 + … + 50 =
  2. 2.1 + 2 + 3 + … + 96 =
  3. 3.1 + 3 + 5 + … + 43 =
  4. 4.1 + 2 + 3 + … + 17 =
  5. 5.1 + 2 + 3 + … + 46 =
  6. 6.1 + 2 + 3 + … + 51 =
  7. 7.1 + 2 + 3 + … + 22 =
  8. 8.1 + 2 + 3 + … + 63 =
  9. 9.1 + 2 + 3 + … + 97 =
  10. 10.1 + 3 + 5 + … + 15 =
  11. 11.1 + 2 + 3 + … + 14 =
  12. 12.1 + 2 + 3 + … + 21 =
  13. 13.1 + 3 + 5 + … + 49 =
  14. 14.1 + 2 + 3 + … + 44 =
  15. 15.1 + 3 + 5 + … + 27 =
  16. 16.1 + 3 + 5 + … + 47 =
  17. 17.1 + 3 + 5 + … + 21 =
  18. 18.1 + 2 + 3 + … + 69 =
  19. 19.1 + 2 + 3 + … + 13 =
  20. 20.1 + 3 + 5 + … + 19 =
  21. 21.1 + 3 + 5 + … + 11 =
  22. 22.1 + 2 + 3 + … + 73 =
  23. 23.1 + 2 + 3 + … + 81 =
  24. 24.1 + 3 + 5 + … + 31 =
  25. 25.1 + 2 + 3 + … + 49 =
  26. 26.1 + 2 + 3 + … + 57 =
  27. 27.1 + 2 + 3 + … + 94 =
  28. 28.1 + 3 + 5 + … + 13 =
  29. 29.1 + 2 + 3 + … + 45 =
  30. 30.1 + 2 + 3 + … + 30 =
  31. 31.1 + 2 + 3 + … + 52 =
  32. 32.1 + 2 + 3 + … + 53 =
  33. 33.1 + 3 + 5 + … + 25 =
  34. 34.1 + 2 + 3 + … + 88 =
  35. 35.1 + 2 + 3 + … + 82 =
  36. 36.1 + 3 + 5 + … + 33 =
  37. 37.1 + 3 + 5 + … + 45 =
  38. 38.1 + 2 + 3 + … + 31 =
  39. 39.1 + 2 + 3 + … + 16 =
  40. 40.1 + 2 + 3 + … + 18 =

Answer key

  1. 1275
  2. 4656
  3. 484
  4. 153
  5. 1081
  6. 1326
  7. 253
  8. 2016
  9. 4753
  10. 64
  11. 105
  12. 231
  13. 625
  14. 990
  15. 196
  16. 576
  17. 121
  18. 2415
  19. 91
  20. 100
  21. 36
  22. 2701
  23. 3321
  24. 256
  25. 1225
  26. 1653
  27. 4465
  28. 49
  29. 1035
  30. 465
  31. 1378
  32. 1431
  33. 169
  34. 3916
  35. 3403
  36. 289
  37. 529
  38. 496
  39. 136
  40. 171

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