How to deal with an arrogant kid?

Im tutoring this kid and he's so arrogant. He believes he's a genuis. In fact, he believes he knows more in math than I do. I know I'm not a genuis either but it just makes me irritated when he looks at what I'm doing and says, PSHH i know all of that. He's in grade 4, so literally all he's learning is simple fractions. I'm in grade 12 so I'm pretty sure I know more than him. I really need the money so I can't quit. I've been pretty calm about it and just shrugging it off, but my gosh. I pulled out when of my previous math tests and I got like a couple wrong, and he just said, I can do WAYYY better than that. I got a perfect on my last test. And hes like UGHH high school seems So easy I'll just pass with 100%! ...How do I deal with him....