1. Print numbers
2. Fix the code: Countdown
3. Numbers
4. Powers of two
5. Powers of base n
6. The sum of consecutive numbers, version 1
7. The sum of consecutive numbers, version 2

1. String multiplied
2. The longer string
3. End to beginning
4. Second and second to last characters
5. A line of hashes
6. A rectangle of hashes
7. Underlining
8. Right-aligned
9. A framed word
10. Substrings, part 1
11. Substrings, part 2
12. Does it contain vowels
13. Find the first substring
14. Find all the substrings
15. The second occurrence

1. Multiplication
2. First letters of words
3. Factorial
4. Flip the pairs
5. Taking turns

1. Seven Brothers
2. The first character
3. Mean
4. Print many times
5. A square of hashes
6. Chessboard
7. A word squared

All subjects are included as comments within the file of each exercise.