How to Calculate the Temperature of a Planet

I was terrified to write half of them because I thought, if I get this wrong, I am never going to hear the end of it. For one chapter about a planet around a binary star, I started doing the math and I got a number that didn't make any sense. It's like, oh, God, I'm in grad school again, having to figure this stuff out. And then I got an answer that made a lot more sense to me. When you do that, it leads you to thinking about trivia, these details like the Earth rises and sets on the moon or here's how quickly the temperature will drop on a planet.