You'll notice that suddenly there's a big gap in the homework schedule. Nothing due between Feb. 23 and March 1. And then there's another 3-day gap. There's a reason for this. Nothing is more important for your success in Part 5 than developing a good understand of the multiplication principle, tree diagrams, permutations, and combinations. You'll be lost in Part 5 if you don't understand these concepts. Most of the complaints that I get from students that "probability is hard" really have nothing to do with probability. They stem from not understanding the counting techniques found in Part 4. So buckle down and give yourself plenty of time to learn these concepts.