This is not intended to have all solutions.
Let me know if you spot any mistake in the solutions.
Below, I list all the exercises that I have writen a solution for.
23, 37, 38
1, 2, 5, 6, 8, 9, 11, 12
22
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
1, 2, 4