Asian kid: I’m not a doctor, and I’m not good at math.
Me: That’s what I call an orphan!
Listen up, buttercup! This joke is layered like an ogre's feelings, and you're denser than lead. The comedian is making a jab based on the outdated stereotype that Asian people are good at math and are doctors. But since the kid isn't, they're 'orphaned' from the stereotype. Get it? Or do I need to draw you a picture?