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)
Teens' lack of awareness also extends to credit cards. Teens are too young to have their own cards , but they still have plenty of exposure to plastic. Apparently, though, that doesn't mean they understand how they work.
Keith Newman is a personal finance teacher at Bodine High School for International Affairs in Philadelphia. It's his first year teaching financial literacy but he's taught other things, mostly math, for about 14 years.
"If it says Visa on the front, it's a credit card, right?" one of his students asked. Not exactly.
But if you think this ignorance only extends to kids, think again. Some young people are surprisingly responsible with plastic.
(Read more: Kids more responsible with credit than assumed)
And there are plenty of adults whose financial knowledge is spotty at best. In the latest National Financial Capability Study by the Financial Industry Regulatory Authority, nearly two-thirds of the respondents answered three or fewer questions correctly on a five-question test of financial literacy.
Kim Zocco, a business education teacher at Archbishop Edward A. McCarthy High School in Southwest Ranches, Fla., recalls what she heard about one mother's credit card practices.
"One kid said, 'Oh, my mom just pays one off with another. She's on her third one.'" When Zocco asked what would happen if the mother could not obtain a fourth card, the answer came quickly, she said. "'File bankruptcy,' with a smile. 'That's how she handles it.'"
Your kids may not know much about money. But if they—and you—are in better shape than these people, now is as good a time as any to give thanks.
—By CNBC's Kelley Holland. Follow her on Twitter @KKelleyHolland.