Assoziativ-Gesetz

$\displaystyle a \cdot \left( b \cdot c \right)$	$\displaystyle =$	$\displaystyle \left( a \cdot b \right) \cdot c$
$\displaystyle a + \left( b + c \right)$	$\displaystyle =$	$\displaystyle \left( a + b \right) + c$