Long ago, I went to a seminar for VideoText and was almost sold ... but I didn't buy it because I knew that my son, who has always greatly disliked and didn't "get" math, would find it difficult. We eventually went with Teaching Textbooks, which was much more what he needed to succeed. So the only thing I can say about it is - it was very popular at that time but more for kids who were okay with or good at math. This is the impression I got - not an actual user, here, but just throwing that out there.
"Ree-bee," Mom to former United States Marine ds and math teacher DIL * artist dd 20 * motion-loving ds 17 * piano-playing ds 12
"For Miss Minnie loved children and she loved books, and she taught merely by introducing the one to the other." from "A Consent," by Wendell Berry