This website is meant to teach in a more personalized learning style, you do need to be a member to use it. They also do have textbooks and the Kansas Standards on the website with the test preparation.
The learning tap contains lessons between Pre-K to Calculus however Math and Language Arts contains games for some grades as well.
The Assessment tab is there to demonstrate a Real-Time Diagnostic tool, if you go to the bottom it sends you to inspiration for families where it talks about:
After doing the test for your students the IXL Analytics shows where each student can improve.