yes, I've had this problem with my DS. It was worse probably around 8/9. At 10, it's a bit better. I have had to tell him numerous times that crying and yelling (on both our parts) doesn't help, that his reaction leads to my reaction, that we both need to calm down and speak calmly and respectfully to each other.
He interrupts a lot when I'm trying to explain something to him because what he wants is just the answer, and not a detailed explanation of how to get the answer. I never tell him the answer. I guide him to get to the right answer, and that frustrates him. I have had to tell him repeatedly that I will *never* tell him the answer.
When/if my DS tells me I don't know what I'm doing repeatedly, I just back off. I say, "OK, then you can figure it out or talk to the teacher." If he brings home the wrong answer (as you stated), then I would write a note or email the teacher and ask the teacher to go over the problem again with your DS because you don't think he's getting it.
The other thing you can try is getting a workbook or find a source online that has the types of math problems he is working on. The workbook and/or online resource should also provide guidance on how to tackle the problem. I think I just got a newsletter from my DS's school about a HW hotline. See if your school has one.