This may be a dumb question, but does anyone else use non-metric measurements besides the US? For metric-measuring countries, how do your recipes break up things? We've got assortments of measuring cups (fractions of teaspoons, tablespoons, cups, and occasionally dry or wet ounces). It's hard to convert and, say, make a triple batch of cookies because you have to remember whether it's three teaspoons to a tablespoon and four tablespoons to a cup (or is it a quarter cup?), or maybe it's the other way around? Then we have some things sold by weight but used in recipes by volume, like chocolate chips (12-oz bags but always measured in cups).
If you're used to metric, are you pretty much expected to be able to convert/multiply quantities in your head, since it's mostly by factors of 10?