First of all, it’s great that your son is going for extra help! Too few students do so.
The key to getting the most out of one-on-one time with a teacher is to ask the right question. So, for example, if you son simply asks, “How do I do this math question?” his teacher’s explanation will probably be very similar to the way it was originally explained in class. The problem is that your son didn’t understand that explanation the first time, so he may not understand it a second time either.
So how can your son phrase his question so the teacher explains the answer in a new way?
Ask a ‘why’ question: Rather than asking “How do I do this question?” try asking “Why does this question work this way?” or “Why is this question answered this way?” Getting an answer from his teacher that explains why the math is done the way it’s done should shed some insight on it for your son. What your son is trying to do is understand the concept as best he can and a ‘why’ explanation often helps.
Ask a ‘what does this build on’ question: If your son’s teacher answers the ‘why’ question with, “Because that’s just the way it is”, I suggest your son change his question to, “What does this math concept build on?” The hope is that your son’s teacher will explain what the most basic and elementary form of this math concept is – the version of it that your son would have seen, and understood, in an earlier grade. Seeing the connection between a simpler version of the math concept from an earlier grade and the ‘new’ more complex version of the same math concept - the one that he’s currently trying to understand - may give your son the insight he needs to be able to make sense of it.
Sometimes a student just can’t get on the same page as their math teacher and, no matter what, they can’t seem to follow some of their teacher’s explanations. If that’s the case with your son, he could try asking another math teacher for help (perhaps a math teacher he had previously), or he could try asking a classmate who is strong in math. \
Important to know: The most important thing is that your son keeps seeking math help, if he needs it, rather than giving up. The fact that he wants extra help communicates that he wants to learn, which is great. If he can’t understand his teacher’s explanations when he goes for extra help, he should be encouraged to seek extra help elsewhere so he doesn’t become discouraged and start giving up on math, as many students do.