Danica McKellar

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 became part of the main cast in the Netflix original series Project Mc2. McKellar has written seven non-fiction books about mathematics: Math Doesn't Suck, Kiss My Math, Hot X: Algebra Exposed, Girls Get Curves: Geometry Takes Shape, Goodnight, Numbers, and Do Not Open This Math Book, which encourage middle-school and high-school girls to have confidence and succeed in mathematics.

Danica McKellar was born on January 3, 1975 in La Jolla, California. She moved with her family to Los Angeles when she was eight. Her mother, Mahaila McKellar (née Tello), was a homemaker; her father, Christopher McKellar, is a real estate developer; her younger sister, Crystal, is a lawyer and former child actor. She is of Scottish, French, German, Spanish, and Dutch descent on her father's side. On her mother's side, she is of Portuguese descent, by way of the Azores and the Madeira islands. In 1998, McKellar earned a Bachelor of Science degree in mathematics (summa cum laude) from University of California, Los Angeles, where she was a member of the Alpha Delta Pi sorority. As an undergraduate, she coauthored a scientific paper with Professor Lincoln Chayes and fellow student Brandy Winn titled "Percolation and Gibbs states multiplicity for ferromagnetic Ashkin–Teller models on Z 2 {\displaystyle \mathbb {Z} ^{2}}." Their results are termed the "Chayes–McKellar–Winn theorem". Later, when Chayes was asked to comment about the mathematical abilities of his student coauthors, he told The New York Times, "I thought that the two were really, really first-rate." As a result of her past collaborative work on research papers, McKellar is assigned the Erdős number four, and the Erdős–Bacon number six.

At age seven, McKellar enrolled in weekend acting classes for children at the Lee Strasberg Institute in Los Angeles. In her teens, she landed a prominent role on The Wonder Years, an American television comedy-drama which ran for six seasons on ABC, from 1988 to 1993. She portrayed Gwendolyn "Winnie" Cooper, the main love interest of Kevin Arnold (played by Fred Savage) on the show. Her first kiss was with Savage in an episode of The Wonder Years. She later said, "My first kiss was a pretty nerve-wracking experience! But we never kissed off screen, and pretty quickly our feelings turned into brother/sister, and stayed that way."

McKellar said that she found it "difficult" to move from being a child actress to an adult actress. Since leaving The Wonder Years, McKellar has had several guest roles in television series (including one with former co-star Fred Savage on Working), and has written and directed two short films. She appeared in two Lifetime films in the Moment of Truth series, playing Kristin Guthrie in 1994's Cradle of Conspiracy and Annie Mills Carman in 1996's Justice for Annie. She briefly returned to regular television with a recurring role in the 2002–03 season of The West Wing, portraying Elsie Snuffin, the half-sister and assistant of Deputy White House Communications Director Will Bailey. McKellar was featured in the video for Debbie Gibson's eighth single from the Electric Youth album, "No More Rhyme", which was released in 1989. She plays the cello in the beginning of the video. McKellar appeared in lingerie in the July 2005 edition of Stuff magazine after readers voted her the 1990s star they would most like to see in lingerie. She explained that she agreed to the shoot in part to obtain "grittier roles". In 2006, McKellar starred in a Lifetime film and web-based series titled Inspector Mom about a mother who solves mysteries. On the August 1, 2007, edition of the Don and Mike Show, a WJFK-FM radio program in Washington D.C., McKellar announced that the producers of How I Met Your Mother were planning to bring her back for a recurring role (she guest-starred on the show in late 2005 in "The Pineapple Incident" and again in early 2007 in "Third Wheel"). She made an appearance on the show The Big Bang Theory, in the episode "The Psychic Vortex". In 2008, she starred in Heatstroke, a Sci-Fi Channel film about searching for alien life on Earth, and in 2009 she was one of the stars commenting on the occurrences of the new millennium in VH1's I Love the New Millennium and was the math correspondent for Brink, a program by the Science Channel about technology. In 2013, she played Ellen Plainview in Lifetime's reimagining of the 1956 Alfred Hitchcock film The Wrong Man. McKellar has also worked as a voice actress, having provided the voice of Jubilee in the video game X-Men Legends (2004), and Invisible Woman in Marvel: Ultimate Alliance (2006) and Marvel: Ultimate Alliance 2 (2009). She provided the voice of Miss Martian in the TV series Young Justice. In 2012, she starred in the Lifetime film Love at the Christmas Table with Dustin Milligan. In January 2013, she starred in the Syfy film Tasmanian Devils with Apolo Ohno. On August 20, 2013, Canadian singer Avril Lavigne released the music video for her single "Rock N Roll" from her self-titled fifth album, which features McKellar as "Winnie Cooper". On March 4, 2014, it was announced that McKellar would be competing on season 18 of Dancing with the Stars. She paired with Valentin Chmerkovskiy. McKellar and Chmerkovskiy were eliminated on Week 8, finishing in 6th place. She had a guest appearance in the sixth episode of Impractical Jokers season four, which was titled "The Blunder Years". She made another guest appearance in season seven, episode ten, "Speech Impediment". In 2015, she starred in the Netflix original series Project Mc2 as The Quail. She has starred in several Hallmark Channel films, including Crown for Christmas, My Christmas Dream, Campfire Kiss, Love and Sunshine, Christmas at Dollywood, and You, Me & the Christmas Trees, as well as the Hallmark Movies & Mysteries series The Matchmaker Mysteries. McKellar was a judge on the single season of Fox's Domino Masters which premiered on March 9, 2022.

McKellar has authored several mathematics-related books, primarily targeting adolescent readers interested in succeeding at the study of mathematics. Her first book, Math Doesn't Suck: How to Survive Middle School Math without Losing Your Mind or Breaking a Nail, was a New York Times bestseller, and was favorably reviewed by Tara C. Smith, the founder of Iowa Citizens for Science and a professor of epidemiology at the University of Iowa in Iowa City. The book also received a review from Anthony Jones, writing for the School Librarian journal, who described the book as "a trouble-shooting guide to help girls overcome their biggest maths challenges," noting what he described as "real-world examples of great mathematics in action." 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". McKellar's second book, Kiss My Math: Showing Pre-Algebra Who's Boss, was released on August 5, 2008. The book's target audience is girls in the 7th through 9th grades. Her third book, Hot X: Algebra Exposed! covers algebra topics, while the previous two titles were intended as "algebra-readiness books." Hot X was published on August 3, 2010. Her fourth book, Girls Get Curves – Geometry Takes Shape, focuses on the subject of geometry, and attempts to make the subject more accessible. Three of McKellar's books were listed in The New York Times children's bestseller list. She received Mathical Honors for Goodnight, Numbers.

McKellar married composer Mike Verta on March 22, 2009, in La Jolla, California; the couple had dated since 2001. They had their only child, a son, in 2010. McKellar filed for divorce from Verta in June 2012. She and her boyfriend Scott Sveslosky got engaged on July 16, 2014. Sveslosky is an attorney and a partner at the law firm Sheppard, Mullin, Richter & Hampton in downtown Los Angeles. On November 15, 2014, they married in Kauaʻi, Hawaii. In 2022, she became an evangelical Christian and is a member of Shepherd Church in Los Angeles. She cites Candace Cameron Bure as having been a major influence in her life after Bure gave her a copy of the Bible.

Chayes, L; McKellar, D; Winn, B (1998). "Percolation and Gibbs states multiplicity for ferromagnetic Ashkin–Teller models on Z 2 {\displaystyle \mathbb {Z} ^{2}} " (PDF). Journal of Physics A: Mathematical and General. 31 (45): 9055–9063. Bibcode:1998JPhA...31.9055C. doi:10.1088/0305-4470/31/45/005.

McKellar, Danica; Mary Lynn Blasutta (2008). Math Doesn't Suck: How to Survive Middle School Math without Losing Your Mind or Breaking a Nail. New York: Plume. ISBN 9780452289499. McKellar, Danica (2009). Kiss My Math: Showing Pre-Algebra Who's Boss. New York: Plume. ISBN 9780452295407. McKellar, Danica (2010). Hot X: Algebra Exposed. New York: Plume. ISBN 9780452297197. McKellar, Danica (2012). Girls Get Curves: Geometry Takes Shape. New York: Hudson Street Press. ISBN 9781594630941. McKellar, Danica (2018). Ten Magic Butterflies. New York: Random House Children's Books. ISBN 9781101933824. McKellar, Danica (2018). Do Not Open This Math Book. New York: Random House Children's Books. ISBN 9781101933985. McKellar, Danica (2019). Bathtime Mathtime. New York: Random House Children's Books. ISBN 9781101933961. McKellar, Danica (2020). The Times Machine. New York: Random House Children's Books. ISBN 9781101934029. McKellar, Danica (2022). Double Puppy Trouble. New York: Random House Children's Books. ISBN 9781101933862. McKellar, Danica (2022). Goodnight, Numbers. New York: Random House Children's Books. ISBN 9780593643556.

McKellar's career in Hallmark mystery films was spoofed in the 2019 film Knives Out, complete with the parody title Deadly By Surprise.