Hotarla, that's an smart question.
Also it's on the end (probably after a few irrelevant-looking questions) so people don't get it too much thought and answer honestly, which is what you want.
Kitalpha Hart wrote:I had one math question
Person gives me $20 for a $12.50 transaction, what do I give them back?
$7.50
Apparently that fifty cents threw a looooooot of people off and they would give back something like $8.50
You ask my grandma who is about to turn 90 and she will answer correctly.
You ask people my age or younger, and some of them can't do a simple everyday substraction correctly.
It's certainly depressing, from a maths teacher point of view.