DETROIT (AP) — Blending commentary with comedy and criticism, Bill Cosby challenged Detroit parents to be more active in their children’s education and back an effort to improve the troubled public schools.

The activist and entertainer said Tuesday that he supports the district’s emergency financial manager, Robert Bobb, and a campaign to retain the schools’ shrinking enrollment. Bobb and Cosby were scheduled to go door-to-door late Tuesday afternoon, to persuade parents to keep their children in, or return them to, the district.

“This has a chance,” Cosby told reporters at a news conference. “And we’re going to knock on these doors because they weren’t open. And we’re going to talk to people to get them to understand the seriousness of a child left without a reason to understand math, without a reason to study and be able to understand English.”

Bobb is pushing the district’s $500,000 student retention campaign called “I’m In.” It features 172 blue doors meant to welcome parents and students to the 172 district schools.

Enrollment dropped below 100,000 last year, and Bobb has budgeted for 83,777 students this fall. Classes begin next Tuesday.

Cosby said he became interested in working with Detroit Public Schools after learning of Bobb’s effort to clean up the district’s finances while improving education.

Since Bobb was appointed in March by Gov. Jennifer Granholm, he has launched a number of audits, uncovering waste and fraud that has cost the district hundreds of thousands of dollars. He has closed 29 schools and laid off more than 1,000 teachers while cutting into a $259 million budget deficit.

Restoring confidence in the district, which is among the worst in the nation in graduation and dropout rates, also is part of Bobb’s mission.

Last month, he began visiting city neighborhoods, meeting with parents who had pulled their children from the district in favor of either private and charter schools or schools outside Detroit.

But Cosby said parents can do a better job of ensuring their children get to school each day.

“We’ve got to really speak to parents — in a way they can understand — that the prison system is smiling, waiting on your child,” he said.

Cosby later entranced several dozen students during a round-table discussion.

He listened to a flood of concerns that included family problems and truancy, then tried to motivate through sometimes blunt advice.

Life and school promise opportunities and time to make decisions, Cosby said.

“Not everybody in this room wants to be a doctor or a lawyer,” he said. “Have you ever thought about being a physical therapist? … Have you ever thought about an electrician? Just a plain, old, raggedy $75-an-hour electrician? How much is eight times $75?

“You don’t know what you’re going to fall in love with until you’re exposed to it.”

Cosby will attend a districtwide rally Tuesday evening at Henry Ford High School.

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