As she punched numbers into a calculator, Luka Fernandez had a lot to figure out. How much could she afford to pay for a car? Should she buy cable? Where should she live? These are the types of questions facing many adults as they try to manage a household budget. But Luka is a 14-year-old pretending to be an adult as part of a financial literacy exercise at the Junior Achievement Finance Park in Fairfax County, Va.

‘‘I don’t know how much my parents spend, but I know they pay more for stuff like groceries,’’ said Luka, an eighth-grader.