Fiona was excited! Her friends were coming over for a pizza party.

She had games, music, and three delicious pizzas ready to share.

Soon, the doorbell rang.

"Pizza!" shouted Fiona's friends as they hurried inside.

Fiona smiled, but then she wondered, "How can I make sure everyone gets a fair share?"

"Right now, this pizza is one whole," she explained.

A whole means that nothing has been divided or taken away.

"Now each piece is one-half, or 1/2, of the whole pizza."

Both pieces had to be the same size to be equal halves.

"The top number is called the numerator. It tells how many parts we are talking about."

"The bottom number is the denominator. It tells how many equal parts make the whole."

Two more friends arrived at the party.

"We need more pieces!" Fiona laughed. "Let's divide another pizza into four equal parts."

"Each piece is 1/4, or one-fourth, of the whole pizza."

Four pieces of 1/4 put together make one whole pizza.

"Fiona! You have 1/2, but I have 2/4. Those fractions look different!"

Fiona looked closely at the two servings. Were they really different amounts?