McKellar studied at UCLA, majoring in mathematics, and graduated summa cum laude in 1998. As an undergraduate, she coauthored a scientific paper[4] with Professor Lincoln Chayes and fellow student Brandy Winn. The paper proves a theorem in mathematical physics that could be called the "Chayes-McKellar-Winn Theorem,"[5] although this appellation is not in widespread use. This paper makes her one of the very few people, with a finite Erdős-Bacon number (Natalie Portman being another notable example). Referring to the mathematical abilities of his coauthor students, Chayes was quoted in the New York Times[6] as saying, "I thought that the two were really, really first-rate." McKellar even provides free online math tutoring for her fans at her official internet website. While a student at UCLA, she was a sister in the Alpha Delta Pi sorority.
McKellar is the author of the book Math Doesn't Suck: How to Survive Middle-School Math Without Losing Your Mind or Breaking a Nail, a book encouraging girls in middle school to enjoy mathematics and be good at it.[7]. The book has been favorably reviewed by Tara C. Smith, the founder of Iowa Citizens for Science and a professor of epidemiology at the University of Iowa.[8] In an interview with Smith, McKellar said that she wrote the book "to show girls that math is accessible and relevant, and even a little glamorous" and to counteract "damaging social messages telling young girls that math and science aren't for them"[9]
McKellar was named Person of the Week[10] on ABC World News with Charles Gibson for the week ending 10-Aug-2007. The news segment highlighted her book Math Doesn't Suck and her efforts to help girls to develop an interest in mathematics, especially during their vulnerable middle school years.[continued]