I don't get why Asians are so good at math. They can barely see the numbers.
What makes you want to tell jokes like that about Asian people?
Just for fun. I mean, ask me about something else.
The stereotype that Asians are good at math is simply not true. In addition, insinuating that Asians can't see is a pretty harmful stereotype based on their appearance. I think you shouldn't use these sorts of stereotypes to make jokes, because they can hurt people.