Kids say the darnedest things. Often, it's a lot of misinformation about money.
The 1,309 teens who took a recent financial literacy test from the National Financial Educators Council scored an average of 58 percent. More than 70 percent of the teens scored less than 70 percent on 30 questions about topics such as creating budgets, deciding how much insurance you need, and the future value of $100 invested monthly at a given interest rate.
(To see how you score, take the test here.)
Want to know what they don't know? The financial literacy teachers who try to educate them are happy to share.
(Read more: Warren Buffett: How to teach your kids about money)
Ruth Sisman, a teacher at Albemarle High School in Charlottesville, Va., asks her students each year to start tracking every penny they spend.
"They say, 'Oh, I don't have any expenses.' I say, 'What about your cellphone?'" Sisman said. Oh, that.
Investing is equally treacherous territory. No financial literacy class would be complete without some discussion of investing, and when it comes to the stock market, what teens don't know could fill a prospectus.
For example, Maggie Wohltmann, a business education teacher at New Jersey's Teaneck High School, found her students getting a bit too excited about stock fluctuations.
"Students think initially that if they buy a product that day it's influencing the stock price that day. They think, 'Oh, I went to McDonald's today. That's why the stock is up," she said.
(Read more: Teaching kids traditionally about money doesn't work)