What type of math does Electrician or plumber need?

I've been thinking about becomeing an electrician, or maybe even a plumber by going to a tech school. But I would like to know what I need to be prepared. What skills are needed? What math level? (Algebra 2)? I'm really really bad at math. I'm in the 12th grade and I'm only in Geometry. (Which is sad) I havent even taken Algebra 2, and that's usually a sophmore class.