Editor's note: The following are questions received from listeners of "RealMoney Radio." To send Cramer a question about topics from his radio show, click here. Listen to Cramer's latest radio show by clicking here. How is free cash flow calculated? -- Jonah from New York James J. Cramer: Free cash flow is calculated by taking cash flow from operations and subtracting capital expenditures. Both of these can be found on a company's statement of cash flows. Free cash flow is an important metric because it gives a rough estimate of how much money a company can put towards share buybacks and dividends. Do you like First Marblehead (FMD)? -- Rodney from Texas James J. Cramer: I believe First Marblehead is a buy, even after the big run it has had this year. The private student loan business is growing very quickly, and First Marblehead is a pure play on that growth. In addition, my buddy Tom Brown over at BankStocks.com is a big fan, and Tom is simply one of the best analysts around. Want more Cramer? Check out Jim's rules and commandments for investing from his latest book by clicking here.