How to file taxes, if you're in the USA. How to calculate interest, balance your books, and set budgets based on your income. You can teach spreadsheets, double entry accounting software, and fun/useful math functions.
More generally, high school students should learn how to model information in a spreadsheet. It can be anything they are interested in: prices on collector's items, tracking their friendships and contacts, graphing their caloric intake per day, tracking the tweets and mentions of your favorite celebrities....
More generally, high school students should learn how to model information in a spreadsheet. It can be anything they are interested in: prices on collector's items, tracking their friendships and contacts, graphing their caloric intake per day, tracking the tweets and mentions of your favorite celebrities....