Danica Mae McKellar (born January 3, 1975) is an American actress, mathematics writer, and education advocate. She is best known for playing Winnie Cooper in the television series The Wonder Years.
McKellar has appeared in various television films for the Hallmark Channel. She has also done voice acting, including Frieda Goren in Static Shock, Miss Martian in Young Justice, and Killer Frost in DC Super Hero Girls. In 2015, McKellar joined part of the main cast in the Netflix original series Project Mc2.
In addition to her acting work, McKellar later wrote seven non-fiction books, all dealing with mathematics: Math Doesn't Suck, Kiss My Math, Hot X: Algebra Exposed, Girls Get Curves: Geometry Takes Shape, which encourage middle-school and high-school girls to have confidence and succeed in mathematics, Goodnight, Numbers, and Do Not Open This Math Book.