So I was wondering, how would I go about figuring out that $0.03 of a bitcoin valued $3,624.88 equals 0.000011 bitcoins without using a calculator?

I feel like this is a stupid question, but for some reason I can't figure it out. I've never been very good at math but this is ridiculous so if you want to call me a fuckass, I understand.

Much thanks in advance.