In a recent column, “Boston isn’t the most expensive place to live. But it’s pretty close.” (Business, May 3), Larry Edelman mentions that, according to an MIT “living wage” tool, a single person needs approximately $47,000 a year to survive in Boston. I think that ought to be net, not gross, income. I make just over $77,000 a year and take home $48,000, and I need a roommate to keep from being completely strapped every month and to create savings. Let’s just live in reality with these numbers.