Porosnok96- I didn't answer your question. He makes a lot of mistakes on challenge word problems. Most of the errors are due to careless reading - when I make him go back and re-read the question out loud, he usually picks up his error.
There are a few that need at least a few written notes- there's just a lot of information to keep mentally (he doesn't write anything down). There is usually one (the last one) that benefits from some form of a list or table to solve.