The drama club ordered 15 pizzas for the cast party if the 25 members ate 12 1/2 pizzas out of the 15 how much pizza did each cast member eat

So we're going to divide those 12-and-a-half by 25 members to find how much each member ate. 12-and-a-half converted into a decimal is 12.50, and 12.50 divided by 25 is 0.5.

Each member had 0.5 of a slice of a pizza, or fraction-wise, each member had half a slice of pizza.