Charlotte Striebel ­picketed, testified and fought for women’s equality over more than two decades.

But it was her expertise with numbers that made the mathematician and University of Minnesota professor a leading advocate for equality at a time when women’s opportunities were more limited and the pay gap was wide.

“She was really a role model for so many people,” said Sue Abderholden, who leads the National Alliance on Mental Illness of Minnesota.

A quiet, straightforward woman with a strong resolve, Striebel attacked a problem by analyzing it, using statistics to show that women were not being treated equally. “She never backed down,” said Abderholden, who met Striebel in the 1970s as members of the National Organization for Women. “She would say: ‘We’re right and we’re going to win. We just have to be in it for the long haul.’ She was quite an inspiration. ... She encouraged younger women to reach for their dreams, whatever they might be.”

Striebel died after a heart attack March 12. She was 84.

Striebel was born in Columbus, Ohio, and was a mathematics professor at the University of Chicago for two years before coming to Minnesota in the mid-1960s, said her daughter, Kathryn Striebel of Oakland, Calif.

“I remember the day she walked in my [university] office,” said Rep. Phyllis Kahn, DFL-Minneapolis. Striebel persuaded her to join the U group WAMS — Women Against Male Supremacy.

“The idea was to get rid of stuff that was highly bene­ficial to men,” Kahn said. At that time, the want ads were “discrimination at its worst,” she said. “Women were always secretaries and men were engineers, technicians.” So the group picketed the Minneapolis Star and Trib­une, protesting the “sex segregated want ads,” she said.

Striebel had an “enormous ability” to treat difficult equity issues in an intellectual way, Kahn said. She provided statistics for the landmark Rajender class-action suit that changed hiring practices at the U and for academic employees across the country.

When state lawmakers took up pay equity for women, Striebel again provided facts. “One of the reasons we went further and faster on these things is that we had this tremendous intellectual background behind everything we were doing,” Kahn said.

Longtime friend Nina Roth­child said Striebel was “very much a feminist. ... She took on the establishment and conventional wisdom about gender roles, was an unabashed agitator who was willing to take risks and who contributed enormously to the advancement of women in the state.”

Gender equality became personal for Striebel when her seventh-grade daughter wanted to swim for her St. Paul junior high school. “But it was a boys team,” said Kathryn Striebel. “They didn’t have a girls swim team.” So her mother filed a complaint and Kathryn Striebel swam.

“The boys and coaches weren’t thrilled about it, but it forced the issue,” she said.

When Striebel wasn’t working with numbers or fighting for equality, she read, listened to opera and music and sailboarded. “She took up [sailboarding] when she was 50,” her daughter said. When she retired in 1994, Striebel moved to South Padre Island, Texas, and sailboarded until she was 82. She took kitesailing lessons at 80 but quit because her friends were concerned she would get hurt, Kathryn Striebel said.

“My mother was extremely independent … strong and very smart,” she said. “When attorneys told her she didn’t know anything about the law, she went and got a law degree in her spare time while raising two kids and teaching.”

She is also survived by her son, Daniel Striebel of Madison, Wis.; brother, Taelen Thomas of Carmel, Calif.; and three grandchildren.

Services have been held.