Susan Graves taught a little and learned a little in her credit union’s partnership with a local middle school. Graves is vice president of branch administration at the $132 million, 16,000-member Oxford FCU in Mexico, Maine. She and volunteers from the credit union recently visited Oxford Hills Middle School for two days of instruction and hands-on activities, including using g a workbook and PowerPoint presentation to teach the basics of using a checking account. Then it was off to a day at Harvest Hills Farms for more learning. For instance, Graves learned how to milk a cow, sort of.