What's 301 minus 75? Only 33 percent of fourth-graders in Detroit know the answer.

In another sad development for the struggling district, local and national officials this morning announced Detroit students in fourth and eighth grade recorded the lowest math scores in the history of the National Assessment of Educational Progress standardized test.

69 percent of fourth graders and 77 percent of eighth graders scored below basic skill levels on the test, given to 18 urban districts across the nation.

One question asked eighth-graders: "In a box of six red pencils, four green pencils and five blue pencils, what is the probability of randomly selecting a green pencil?"

Only 34 percent of Detroit students answered correctly, compared to a national average of 77 percent and a large-city average of 67 percent.

Concerned by the results, Michael Casserly, executive director of the D.C.-based Council of the Great City Schools, flew to Detroit to discuss the results.

He said scores were "only slightly better than what one would expect by chance as if the kids had never gone to school and simply guessed at the answers," and called for a complete overhaul of the school system.

Robert Bobb, appointed this year by Gov. Jennifer Granholm as emergency financial manager for the Detroit Public Schools, agreed.

"You'll never move the dial if you're afraid to know where you are,"

, calling the results a "wake-up call" for the city.

Mayor Dave Bing called on parents, teachers, administrators and lawmakers to rally together to address the situation.

"If we do not improve our scores and have a well-educated workforce, we will not be able to attract new businesses and job opportunities for our residents," he said in a released statement. "We can not afford to lose another child.”