I also pulled out building blocks and demonstrated the concept of cubing a number or squaring a number. We did a lot of hands-on things to show him math in the real world.
I think I used CD cases to show him "times" and explained that "times tables" were originally people doing tile counting just like this and how if it was "4x2" it was 4 down one side and two down the other and it adds up to eight and you can count them.
I demonstrated for him that multiplication was shorthand for lots of addition and exponents were shorthand for lots of multiplication and learning this stuff would make your life easier, not harder, because it was a whole lot of shortcuts for stuffing lots of numbers into a small amount of writing.
He was so mad when I finally explained to him that "algebra is just them calling the blank space in your equation X so you can move it around." He was fuming and I don't think he has ever gotten over being mad because his response to that was "That's it! They made that seem hard?! I've been doing that in my head to calculate damage in video games for years!!!!!!" and he stomped off furiously.
He wasn't that old. He was in elementary school at the time and he's really bad at math.