If you add all the numerators and all the denominators in a set of equal fractions, the result is a fraction equal to those in the original set.

If you got an A on a test and a C on homework, do you have a B average?

Lou Abbott and Bud Costello had a comedy routine about baseball called, "Who's on First?"

In the challenge, two players began the day with the same batting average. Lieberthal batted 1.000 while McEwing batted .800, yet McEwing ended the day with the higher cumulative batting average. Such unexpected results are called Simpson's Paradoxes, after Thomas Simpson, a mathematician who worked in the 1700s.