I started playing with the IXL app last night. It allows you to use the materials as a guest but there is a daily limit on how many problems can be done. It has practice problems for grades K to Algebra II. I like it because it has the problem, allows the student to work it out and enter the answer. If the student is wrong, then the program shows the student what the answer should be and how to get it. It reviews the process and actually shows the math involved. I like that because students get immediate feedback and do not have to wait. The app is free but if you want unlimited access to IXL then you need to pay a yearly fee. Since I have 5 classes, I am going to have to make sure I do not assign more than two classes per day on it so that I do not use up the allowed amount of free problems per day.
I like that it has a variety of topics for each class and has Algebra I, Algebra II and Geometry.
I've found it is often hard to find things for High school math that are low cost or free. I like this and plan to integrate it into my classroom. It will help the students monitor their learning as long as they actually read the explanations.