Unit 4 is Big Data & Privacy. It's Unit 5 where the actual coding happens. After teaching this course, I feel that waiting so long before the students do some real coding is a significant weakness. My students have been chafing at the bit to begin writing their own code. I actually leap-frogged Unit 4 and went right from Unit 3 to Unit 5, then went back to do Unit 4. If you only have a few classes left, I suggest going right to Unit 5. The coding is elementary and won;t be over the student's heads. There is nothing in Unit 4 that prepares students for Unit 5 that I could see. I encouraged students to skip right to Code View in the online exercises and to eschew the default block coding so they could get more of the experience of writing actual code. the activities are so tightly scripted that almost any student can work through them at their own pace. I even had a couple of students who went through almost all the Unit 5 lessons on their own, the first weekend, so they could work on other coding projects during class time.