[smithbits]

I think the author is making an excellent point about needing better math in journalism. An article in the NY Times yesterday about online shopping China had this line (pulled from a press release) "Tmall.com, one of Alibaba’s shopping sites, said Chinese bought...two million pairs of underpants, which if linked together would stretch 1,800 miles..." Why should I believe the rest of the article when the author is quoting someone saying that underpants are 57 inches wide?

[BlackJack]

To cross check your claim about the author, I did:

1800 miles ~ 2000 miles 5280 ft/mile ~ 5000 ft/mile So 10M ft / 2M underpants = 5 ft/underpant. 12*5 = 60 in/underpant, which is close to 57, so I trust your statement :)

I think this sort of "back of the envelope" calculation is something that just comes by practice/habit and is not some innate ability. I love this article by Jon Bentley on the topic: http://www.csie.fju.edu.tw/~yeh/research/papers/os-reading-l...

[sveme]

Sorry, but you Americans need to get rid of that imperial system: 1800 miles ~ 2000 km = 2,000,000 m. Each pair is around a metre. Simple, isn't it? Okay, admittedly, 1800 miles is definitely more than 2000 km...