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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 576 · 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 + … + 78 =
  2. 2.1 + 3 + 5 + … + 9 =
  3. 3.1 + 2 + 3 + … + 59 =
  4. 4.1 + 3 + 5 + … + 25 =
  5. 5.1 + 3 + 5 + … + 47 =
  6. 6.1 + 2 + 3 + … + 8 =
  7. 7.1 + 2 + 3 + … + 52 =
  8. 8.1 + 2 + 3 + … + 67 =
  9. 9.1 + 2 + 3 + … + 99 =
  10. 10.1 + 2 + 3 + … + 90 =
  11. 11.1 + 3 + 5 + … + 31 =
  12. 12.1 + 2 + 3 + … + 10 =
  13. 13.1 + 2 + 3 + … + 9 =
  14. 14.1 + 2 + 3 + … + 12 =
  15. 15.1 + 2 + 3 + … + 58 =
  16. 16.1 + 2 + 3 + … + 75 =
  17. 17.1 + 2 + 3 + … + 37 =
  18. 18.1 + 3 + 5 + … + 15 =
  19. 19.1 + 2 + 3 + … + 31 =
  20. 20.1 + 2 + 3 + … + 60 =
  21. 21.1 + 2 + 3 + … + 82 =
  22. 22.1 + 3 + 5 + … + 23 =
  23. 23.1 + 2 + 3 + … + 96 =
  24. 24.1 + 2 + 3 + … + 94 =
  25. 25.1 + 3 + 5 + … + 11 =
  26. 26.1 + 2 + 3 + … + 45 =
  27. 27.1 + 2 + 3 + … + 6 =
  28. 28.1 + 2 + 3 + … + 69 =
  29. 29.1 + 2 + 3 + … + 41 =
  30. 30.1 + 2 + 3 + … + 29 =
  31. 31.1 + 2 + 3 + … + 64 =
  32. 32.1 + 3 + 5 + … + 43 =
  33. 33.1 + 2 + 3 + … + 27 =
  34. 34.1 + 2 + 3 + … + 86 =
  35. 35.1 + 3 + 5 + … + 19 =
  36. 36.1 + 2 + 3 + … + 95 =
  37. 37.1 + 2 + 3 + … + 50 =
  38. 38.1 + 2 + 3 + … + 17 =
  39. 39.1 + 3 + 5 + … + 13 =
  40. 40.1 + 3 + 5 + … + 27 =

Answer key

  1. 3081
  2. 25
  3. 1770
  4. 169
  5. 576
  6. 36
  7. 1378
  8. 2278
  9. 4950
  10. 4095
  11. 256
  12. 55
  13. 45
  14. 78
  15. 1711
  16. 2850
  17. 703
  18. 64
  19. 496
  20. 1830
  21. 3403
  22. 144
  23. 4656
  24. 4465
  25. 36
  26. 1035
  27. 21
  28. 2415
  29. 861
  30. 435
  31. 2080
  32. 484
  33. 378
  34. 3741
  35. 100
  36. 4560
  37. 1275
  38. 153
  39. 49
  40. 196

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