I have two children who are in college. They are full time students and both have part time jobs. During the school year, my son lives in a frat house on campus and my daughter shares an apartment with two other students off campus. They pay their rents and expenses with the money they make and student loans. To determine if I can claim them as dependents, I need to answer if they pay more then half their living expenses with earned income. How do I determine that?