Oh, dear, you’ve been simply dividing by 10 so long you’ve gotten real bad at math. Let’s ask Google:
https://www.google.com/search?q=how+many+feet+in+2815+miles
The answer is 1.4863e+7 or 14,863,000. In other words about 15,000,000.
Although, I’ll give you the benefit of the doubt and consider that perhaps we’re just using different punctuation systems come to think of it…
American units are weird. Something like 4 feet in a yard. 3 bullets in a head. I don’t understand it all.
I don’t think it’s nearly as daft as, say, doing weight in stones, but there was a time when I knew conversions to a number of archaic measurements like rods, chains, and taels.
Ounces might be the goofiest current measurement given that it varies with context. I don’t really have a problem with metric (aside from it occasionally stealing 3.1 ounces my soda), though I’m more comfortable with imperial (and can indeed do rough measurements in it with living body parts).