The number that caught my eye in The New York Times was $9.8 billion. But that staggering sum – the loss recorded by Citigroup – was just the start of the bad news. The fine print was a lot worse.

We all know the cause: Subprime. But if only it had been so good as the headline!

The real number was $22.2 billion – the amount Citigroup wrote off in “soured mortgage-related investments and bad loans.”

Let’s try to get our arms around these numbers by thinking not in terms of dollars, but of seconds. A second goes by pretty quickly, right? A few hundred have ticked by since I started writing this item. So intuition might tell you that any fifth grader would have lived at least a couple billion seconds.

Not so. That fifth grader won’t be a billion seconds old until he’s nearly 32. You do the math.

The way numbers get tossed around these days, we forget just how much a billion really is. So $22.5 billion is simply beyond our comprehension. Yet that’s just one company’s subprime pain.

But remember, Citicorp only reported a loss of $9.8 billion. So where did they get the other $12 billion-plus? From new money poured into the business by investors, including former Chairman Sanford Weill and the governments of Singapore and Kuwait. That’s on top of another $7.5 billion stake Citicorp sold in November to the Abu Dhabi Investment Authority.

During the height of the lending spree, it never occurred to borrowers that home prices wouldn’t go up forever, or that a day of reckoning would come. They can be forgiven; many of them were young and inexperienced. Most of them aren’t real estate professionals.

But the lenders should have known better. So should the real estate professionals who guided customers to mortgage originators who advised them take out “liar loans” and adjustable rate mortgages that were certain to go up.

So now, we have the #8 company on the Fortune 500 “list of America’s largest corporations” turning increasingly to investors in Asia and the Middle East for cash to cover its mistakes.

At about this point in every cycle, we all swear we’ll be wiser next time around. But when the next time comes, we’ll once again hear the four fatal words: “This time it’s different.” And too many people will believe them once again.