What Is a Fraction?

Rational numbers, better known as fractions, play a very important role in your daily life: You use them when cooking or baking, you use them when sharing food with a friend, and they’re everywhere in the financial world. Since rational numbers are written differently than integers, the calculation rules are also different.

A rational number can be written as $\frac{a}{b}$, where $a$ and $b$ are integers ($a,b\in \mathbb{Z}$). A rational number can also be written as a decimal number. In other words, a rational number can be written as a fraction, a decimal number, or an integer.

From this point on, we will call rational numbers “fractions.” A fraction is also a division operation. A fraction is said to “have no remainder” when the answer is an integer.

You can use fractions as a way of determining how to share something. If you’re going to share a piece of chocolate with a friend, you each get half a piece. With fractions you can express this in a mathematical way.

A fraction consists of a numerator, a fraction bar, and a denominator. The number above the line is called the numerator, the line itself is called the fraction bar, and the number below the fraction bar is called the denominator. The numerator tells you how many parts you have, and the denominator indicates how many parts there are in total.