Brighteyes (13) is pretty cool with most of the world having relative values as long as math does not. Math is where she goes for certainty.
Yesterday she found out algebra has statements with varying levels of truthfulness. The resulting explosion was not pretty, and she wasn't happy the rest of the day.
We backed off on that topic. She's buried herself in A Connecticut Yankee in King Arthur's Court for solace. I've never met a bigger Mark Twain fan.