Go ! $2+3\cdot 4$ = 2+12 = 14 $2\cdot 2 - 2$ =   $2 - 2\cdot 2$ =   $2\cdot 4 - 3\cdot 2$ =   $(-2)\cdot 4 - (+3)\cdot(-2)$ =   $-(-2)\cdot(-4) + (+3)\cdot(-2)$ =