My daughter's math is all on tablet. I don't even know how to help.
I feel like it was better when we had a book. We would read a couple pages on the lesson and then move on to the problems. We could go back and reference earlier topics.
Now they just click through quizzes on some app or a website for extra help.
The columns should probably break down and resize to 100% for mobile devices - your 420px container.
I'm not sure what will fit in a the one, two, and three width columns... possibly an image. But the wrapping text in each column for the 420px container is going to look a bit off.
The color scheme on that page is so washed out that my eyes did a double take. That's one thing I wish a designer knew about users - not everyone is using a crisp iMac to view a website. I'm on my already washed out PC and their color scheme makes it even worse.
I feel like it was better when we had a book. We would read a couple pages on the lesson and then move on to the problems. We could go back and reference earlier topics.
Now they just click through quizzes on some app or a website for extra help.