I need a clearer understanding of how to solve: Laticia knitted 4 pairs of socks for her nephew. She did such a good job that everyone asked her to start selling them. In the first week, she knitted 12 pairs of socks. In the second week, she knitted 4 more pairs than the week before. On the third week, she only knitted half of the total of the first two weeks. In the fourth week, she knitted 3 fewer pairs than the week before. How many pairs of socks did Laticia knit altogether?