"Check please?!"

Bills, checks, and money are always around us an require quick math.

One night we went into the French Quarter for dinner as a group. At the end of the meal everyone's "math light" turns on! "We gotta do the bill," we say. Finding the tip can be complicated unless you know the trick of finding 10% of the bill and then working from there. We gave 15% so we found 10% and then added half of 10%, which would be 5%.