The one that got me on an IQ test when I was 12: I needed to know how many items were in a gross. I had never had that term prior to that, so I had to guess. Before the end of the day, though, I knew it was 12 dozen.
Even though she knew the right answer, I wasn't comfortable with how she arrived at it. I showed her for this, convert it to ounces.
I need to work with her on division in a while. Cookies first, though!