Originally Posted by MegMeg
"About 8" could mean "somewhere between 7 and 9." Or it could mean "somewhere between 7.99 and 8.01." It all depends on your definition of "about." I still think the most correct answer is to do the exact calculation -- this is your least biased estimate of the real (unknown) value.

The mathematically correct answer (admittedly a bit absurd on its face) is to use one significant digit and round accordingly; I'm quite sure of this. But I also think that the correct 50,000 answer and the discussion we're all having here is math's way of saying, "You shouldn't do this calculation with only 1 significant figure. Go back and get another one to tack onto that 8, and then your answer will start making sense."

I suspect that the people who wrote the problem didn't have the slightest clue about what they were doing. And of course, with so many problems as bad as this one floating around, it's no wonder that so many American kids bomb out when they get to algebra.