# Fractions and Their Operations

A fraction corresponds to a number of the form

$\displaystyle{\frac{a}{b}}$

where $$a$$ and $$b$$ are integer numbers, and it can be thought as “$$a$$ divided by $$b$$”. For example, the numbers

$\displaystyle{\frac{3}{4}}, \displaystyle{\frac{8}{9}}, \displaystyle{\frac{-3}{4}}$

are fractions. The only restriction for the fraction $$\displaystyle{\frac{a}{b}}$$ is that $$b \neq 0$$, because in that case the fraction is undefined.

Sum of Fractions

The easiest case is when the denominators coincide. In fact, in that case, we find that: