Do they teach personal finance in high school?

It is an Elective \

I get annoyed when the Girl at the checkout has No idea what to do with the 50 dollar note and 25 cents

when the Bill is 30.25 they Give you the change and the 25 cents and when you ask for a 20 dollar Note they say we dont give that Kind of Change 

Many schools offer a class like that as an elective option in high school. 

not so's you'd notice -- no

They teach math skills. Your parents should teach you life skills. 

Sadly, no.

Schools teach the basics. Application of lessons learned are up to the students.

IMO, schools should be teaching more "life skills"...like personal finance (how banks work, how credit cards work, checking & savings account, etc.).

For over 40 years they've been teaching Home Ec (learning to shop for the best groceries deals on a tight budget, cooking,etc.).

I think it's not different from them teaching personal finances.

FWIW, it's actually the parents responsibility for it, but many of them don't know themselves. 

Anyone who's dropped out of high school barely knows how to read.  That's why they are in minimum wage jobs and broke all the time.

Isn't that microeconomics? I know it's taught in college.