For Any Real Number A

Essay

For any real number a, $\left\{ \begin{array} { l } \text { If } a \geq 0 , \text { then } | a | = \underline { \quad \quad \quad \quad }\\\text { If } a < 0 , \text { then } | a | = \underline { \quad \quad \quad \quad }\end{array} \right.$