The White House on Thursday was unable to answer a question critical to the fate of President Obama's push for universal preschool: What is the price tag?

The president traveled to metro Atlanta on Thursday, where he called for guaranteed schooling for 4-year-olds nationwide. Missing from his speech, however, was how much the initiative would cost or specifically where the money would come from.

It's not just education but also the president's push for heightened government spending on infrastructure, manufacturing and green energy that has some questioning whether the White House is using fuzzy math.

In his State of the Union address, Obama insisted that a series of new government investments would not add a dime to the deficit. Numbers crunchers are still waiting to put that claim to the test.

"He's offering an all-you-can-eat diet while saying you can lose weight," said former Congressional Budget Office Director Douglas Holtz-Eakin. "It sounds too good to be true."

Asked about the cost of universal preschool, administration officials Thursday said they would provide figures when the president submits his budget to lawmakers next month. Traditionally, the White House sends its budget to Congress in February.

A study by the liberal-leaning Center for American Progress, however, estimated that universal preschool would cost $98.4 billion over the next decade. An expansion of child care programs and Head Start, also included in the president's blueprint, would cost tens of billions of dollars more during that time period.

Still, the president told the Georgia audience on Thursday that universal preschool would save money.

"Every dollar we invest in high-quality early education can save more than $7 later on -- boosting graduation rates, reducing teen pregnancy, reducing violent crime," he said.

Republicans countered that Obama was proposing publicly popular ideas while downplaying the fiscal barriers to enacting them.

"It's easy to go out there and be Santa Claus and talk about all these things you want to give away, but at some point, somebody's got to pay the bill," said House Speaker John Boehner, R-Ohio, on Thursday.

Under the White House plan, the federal and state governments would partner to provide preschool to all 4-year-olds from families at or below 200 percent of the poverty line -- $46,000 for a family of four.

Some education analysts said universal preschool was needed to level the playing field for low-income children lacking resources during a crucial period of development.

"Scientific discoveries tell us that a great deal of brain development occurs in the first five years of life," said Kenneth Dodge, director of the Center for Child and Family Policy at Duke University. "If we are investing in education from kindergarten forward, we should invest in preschool as a way to improve those outcomes."

But Georgia, one of the states Obama touted as the model for his education proposals, has one of the lowest high school graduation rates in the country -- and some said the president's blueprint would not improve results.

"President Obama's call to expand government preschool and child care is bad policy," said Lindsey Burke, an education fellow at the Heritage Foundation. "The administration should be working to trim duplicative and ineffective programs and leaving the provision of early childhood education and care to private providers and, most importantly, parents."