Danica Mae McKellar (born January 3, 1975), is an American actress and mathematician. As a result of this unusual combination of interests, McKellar has an Erdős–Bacon number of 6. She is best known for her role as Winnie Cooper in the television show The Wonder Years, and now as author of the nationally bestselling book, "Math Doesn't Suck," which encourages and empowers middle-school girls with mathematics know-how.

Together with her younger sister, Crystal McKellar, she began acting at a young age in her mother's dance studio. In 1982 the family moved to Los Angeles and a few years later she appeared in her first commercial. A few guest appearances in "Twilight Zone, The" (1985) was followed by her breakthrough in "Wonder Years, The" (1988). She has had good grades in math and French. In her spare time she likes to go skiing, swimming and surfing.

Best known as America's alluring dream girl from her days as Winnie Cooper on "Wonder Years, The" (1988), Danica McKellar made her breakthrough at the early age of 12. After that show ended, she went on to graduate Summa cum Laude from UCLA with a degree in Mathematics, and even proved a new math theorem, the Chayes-McKellar-Winn Theorem. Since returning to acting, Danica became familiar again to audiences from her year-long turn as the sardonic, dry-witted Elsie Snuffin on "West Wing, The" (1999) in its 4th season. Since then, Danica made guest appearances on shows such as "NYPD Blue" (1993), "Jack & Bobby" (2004), "Eve" (2003), "Navy NCIS: Naval Criminal Investigative Service" (2003), and she played a strung-out heroine addict on Lifetime's "Strong Medicine" (2000). Danica got her feet wet as a filmmaker with her award-winning short film Speechless... (2001) (co-starring "Wonder Years, The" (1988) pal Dan Lauria), which she wrote, directed, and produced. Danica made her debut lingerie spread in the July 2005 issue of Stuff Magazine, in which she appears on the cover. Her pictures can also be seen on its Web site. Talk about allure.