WASHINGTON (AP) — It's a startling statistic on the state of American schools: An estimated 280,000 teaching and other education jobs could be lost in the coming year, according to the White House.

As the Senate prepares for a showdown vote on the jobs bill Tuesday, President Barack Obama is promising to not only save the education jobs at risk, but to support a total of 400,000 education jobs by actions such as rehiring teachers already laid off.

In estimating the potential number of jobs that could be lost and how many his plan could save, the White House makes giant leaps. A look at the claims and how they compare with the facts:

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OBAMA: "Now, this bill will prevent up to 280,000 teachers from losing their jobs. This bill will support almost 40,000 jobs right here in the great state of Texas. So here's what I need you to do: Tell Congress to pass this bill and put teachers back in the classroom where they belong," Obama said Oct. 4 at Eastfield College in Mesquite, Texas.

THE FACTS: There's no doubt that public schools, which rely heavily on state dollars, are hurting. Since 2008, when the economy collapsed, about 294,000 education jobs have been lost, according to the Bureau of Labor Statistics. That figure includes not only public school teachers, but also administrative and support personnel and employees of colleges and universities. In desperation, school districts have not only laid off teachers and aides but taken measures such as eliminating pre-K programs, going to a four-day school week and cutting bus routes.

Obama is predicting that without his legislation, nearly as many jobs will be lost this school year as in the past three school years combined. In a report released this month titled "Teacher Jobs at Risk," the White House says "as many as" 280,000 teacher jobs are at risk in the coming year. But to get to that number, the White House makes a lot of assumptions.

The administration says it started with projected state budget shortfalls in a report from the liberal Center on Budget and Policy Priorities. It then made a series of assumptions, including that spending cuts in each state would be applied proportionally across major budget categories, and that school salaries would be cut in proportion to their share of total spending for K-12 education. The spending cuts were then converted into numbers of jobs based on teacher pay in each state.

Even the group the White House relied on for its data says you can't do that. The Center on Budget and Policy Priorities said in another report that "it is not possible to calculate directly the additional loss of jobs resulting from state education budget cuts."

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WHITE HOUSE REPORT: Obama's plan, which would invest $30 billion in preserving teacher jobs, "will provide support for nearly 400,000 education jobs, enough for states to avoid harmful layoffs, rehire tens of thousands of teachers who lost their jobs over the past three years, preserve or extend the regular school day and school year, and support important after-school activities." It said funding would be targeted to districts most in need of support, especially those with a high share of students living in poverty.

THE FACTS: As the Obama administration learned in its first round of economic stimulus spending, it's nearly impossible to quantify how many jobs are created or saved through infusions of federal dollars. In that $787 billion program two years ago, the White House eventually abandoned its controversial method to count jobs after numerous errors were found.