WASHINGTON  News reports about the upheaval in the world of finance have been full of esoteric terms like “mortgage-backed securities” and “credit-default swaps,” but the crisis has resonated for people who know little about Wall Street and who did not think they would ever have to know. Here are several questions and answers of concern to Main Street Americans:

Q. The bailout program being negotiated by the Bush administration and Congressional leaders calls for the government to spend up to $700 billion to buy distressed mortgages. How did the politicians come up with that number, and could it go higher?

A. The recovery package cannot go higher than $700 billion without additional legislation. As for that figure, it lies between the optimistic estimate of $500 billion and the pessimistic guess of $1 trillion about the cost of fixing the financial mess. But the $700 billion is in addition to an $85 billion agreement on a bailout of the insurance giant American International Group, plus $29 billion in support that the government pledged in the marriage of Bear Stearns and JPMorgan Chase. On top of all that, the Congressional Budget Office says the federal bailout of the mortgage finance companies Fannie Mae and Freddie Mac could cost $25 billion.

Q. Who, really, is going to come up with the $700 billion?

A. American taxpayers will come up with the money, although if you are bullish on America in the long run, there is reason to hope that the tab will be less than $700 billion. After the Treasury buys up those troubled mortgages, it will try to resell them to investors. The Treasury’s involvement in the crisis and the speed with which Congress is responding could generate long-range optimism and raise the value of those mortgages, although it is impossible to say by how much.

So it would not be correct to think of the federal government as simply writing a check for $700 billion. It is just committing itself to spend that much, if necessary. But the bottom line is, yes, this bailout could cost American taxpayers a lot of money.