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

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: