D1
Decision Mathematics 1 is a thrilling blend of algorithm and methodology for solving problems that involve making decisions. For much of the course you need to put yourself into the mind of a dumb computing machine, much like the one that is processing the data from this website right now. A lot of the processes (or "algorithms") are designed for a machine to follow. Your task is to understand these processes today, to become the programmer of tomorrow.
There are six sections in the syllabus for D1. Please note that I am not following any particular text book's order; I am following Edexcel's specification's order of topics (although most text books are quite similar in the order they go in).