I do, but how much depends on what he brings home. If it's math, not at all. That is easy for him. If it's something that I think is a little advanced then I get involved as much as I need to for him to learn. For example, rather than giving him an answer I ask the questions needed for him to figure it out, kind of like leading him to a conclusion without actually giving them the answer. OR, I will have him try something himself and then go over how we can make it better. The second choice is a little harder since my son is such a perfectionist. It's hard to make him "guess" but I try really hard to get him used to that. I may also give my son a tidbit of information that will get him started and let him fly once he gets the concept.
I do have to be careful though. My son is very smart, more than I give him credit for sometimes, and he uses that to manipulate me 