He points to it saying: "This is jiao(角), and also “feet” is jiao(脚). They sound the same!"
Oh, so a corner, or angle, and feet sound the same in Chinese?
"Yeah. Do they know what a corner is in America?"
Yup, they do!
"What about 10x10?"
I don't know, you can ask them.
"What about 10x10+10? What about 12x3-12 and 12x2? The last two equations have the same answer. What about 10x11x10?" He asks as he writes equations on a sheet of paper. "Don’t show them the answer, so they can learn something." He warns. "Only the teacher can see the answer. This is second-grade math. I’m giving them math homework."