Finally, It All Adds Up : Josh Kornbluth’s calculus crisis is fodder for stage show, foundation for philosophy.

Josh Kornbluth was tooling along, headed straight for fame and glory as the world’s uber-mathematician, when he suddenly came to a curve.

It was calculus, and for all the priming he got from his math-teacher father, he just couldn’t fathom his integral calculus class during his freshman year at Princeton. So he shifted gears.

That led him to think about the curves life throws everyone and eventually he came up with his one-man show “The Mathematics of Change,” which he brings to the Irvine Barclay Theatre on Friday.

“My father had always described calculus as being really sexy and exciting [because] you deal with all kinds of curves instead of straight lines,” Kornbluth said during a phone interview from his Berkeley home last week on the day he turned 40. “It’s a whole different way of thinking that I could just not figure out.”

In his 90-minute show, which he premiered in 1993, Kornbluth portrays multiple characters, ranging from his childhood self to his nay-saying grade-school math teacher to his Marxist father.

There is math in the show--his primary props are a large blackboard and chalk used to demonstrate math tricks--but no quiz when he’s done.

“Math is the medium, but it’s actually about going out into the world and hitting the wall, in whatever form . . . about having these fixed ideas, then finding out as a grown-up that you can’t achieve them.

“People seem to identify intensely with that. The question is, what do you do then?”

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In his case, it meant switching majors, to political theory, then working an assortment of jobs, including copy editor and sometime writer (“I was famously bad with deadlines,” he said) for weekly newspapers in Chicago and Boston.

He stumbled into performing when he and some co-workers put together a mock radio show at a going-away bash for an editor. The show, “The Urban Happiness Radio Hour,” was picked up by a Boston station for a while. Although one artist compared it to “a really low-budget ‘Prairie Home Companion,’ the show didn’t capture a big listening audience.

Still, Kornbluth was smitten, and soon went on to produce one-man shows based on subjects ranging from the personal ads, to growing up with Communist parents, losing his virginity, and a long-term position as a legal secretary.

Two--”Red Diaper Baby” and “Haiku Tunnel”--were optioned as feature films by divisions of Universal and Miramax, respectively. Both scripts were developed by Kornbluth at the Sundance Screenwriters Lab, but neither panned out. Undaunted, Kornbluth is working with his brother to release “Haiku Tunnel,” which spoofs the corporate and legal world, as an independent film.

He’s also touring a new show, “Ben Franklin: Unplugged,” which uses Franklin’s life, and his own, to raise issues about father-son relationships. Kornbluth’s own son, 20-month-old Guthrie, has him thinking in new directions.

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Guthrie and Turtle Boy, actually. Kornbluth says he recently recorded several songs with the Bay Area-based a cappella musical group the Bobs. The songs are based on the thrilling adventures of Turtle Boy, his pet turtle of many years.

“My dream is to do some sort of kids’ musical,” he said. “Who knows? Maybe Turtle Boy will get picked up by somebody.”

* Josh Kornbluth presents “Mathematics of Change” Friday at 8 p.m. at the Irvine Barclay Theatre, 4242 Campus Drive, Irvine. $15-$18; half-price tickets are available to full-time students with ID. (949) 854-4646.