His Argument Doesn’t Add Up

(I often tease my girlfriend and call her a lesbian. We’ve decided she’s actually half bisexual.)

Me: “You always round up to the nearest whole if you have half or more, right?”

Girlfriend: “Yeah?”

Me: “Well if you’re half bi, then you’re all bi, which would make you half lesbian.”

Girlfriend: “Hmm.”

Me: “And if you’re half lesbian, you’re all lesbian. Therefore, you are a lesbian.”

Girlfriend: “Well, I can’t argue with math!”