For the current unit 4, refer to Chapters 12-13 on this website. I know these chapters don’t line up to our textbook because it’s an earlier edition.
When you click on the link, go to the drop down menu at the top left of the page. Select a chapter. Right below where you choose the chapter you’ll see quiz. There is a 10 question quiz over each chapter I’d encourage you to take. Also, I’d encourage you to look under where it says more resources and click on worked problems. There you can work more problems and see the solutions. These are two good resources that you can use on each of the chapters in the unit. Some of the materials on the site with the * you will not be able to access but the quiz and worked problems you can.