BOSTON (AP) — A 15-year-old high school student visiting Boston’s Museum of Science has uncovered a math error in the golden ratio at a 34-year-old exhibit.

Virginia resident Joseph Rosenfeld was visiting the museum on a recent family trip when he saw something that appeared wrong with the equation.

Joseph noticed minus signs in the equation where there should have been plus signs. He left a message at the desk and later received a letter from the museum’s exhibit content developer, Alana Parkes, informing him the equation would be corrected.

Parkes wrote that the mistake had been there for a “very long time” without being noticed.

Joseph tells Boston.com (http://bit.ly/1fiu3PH ) that catching the error was exciting. He hopes to return to the state someday to attend the Massachusetts Institute of Technology.