In Belgium, you can buy jam in returnable jars, and once I finished my jar, and was cleaning it, and in the glass at the bottom was "3/8 L". And this sort of threw me, because I was a big metric fan, and the great advantage of the metric system was that it got rid of all those silly fractions. So why were they using them here in metric-land? Then I figured the jar was only so big, so it took up less space to print 3/8 L rather than 0.375 L. But there was another possibility. That being that...