One idea for Algebra, which has worked very well for us (in trying to keep with the Foerster's books) has been the Math Without Borders flashdrives. I particularly liked the section where the author explains how to evaluate a child's understanding of mathematics as a homeschooling parent. Following this guidance, I began asking my sons general questions about the material, and asking them to explain to me in general terms what they were studying and learning (we still have to do many lessons together, and I do have to check that they have actually reworked each problem which they get wrong) This approach has been very helpful. I would recommend the videos/pdf files in the flash drive. I am not sure that I would have wanted to tackle math at home without this additional help. All the best to you