My algebra is rusty and I have a test on Monday. I know the material by the back of my hand but I'm worried I'll fuck up calculating something. What are some internet applications that will test the full extent of my algebraic abilities?

My algebra is rusty and I have a test on Monday. I know the material by the back of my hand but I'm worried I'll fuck up calculating something. What are some internet applications that will test the full extent of my algebraic abilities?