\[\boxed{\mathbf{516\ (516)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ 4 \cdot 12 + 18\ :(6 + 3) =\]
\[= 48 + 18\ :9 = 48 + 2 = 50\]
\[2)\ 4 \cdot (12 + 18\ :6 + 3) =\]
\[= 4 \cdot (15 + 3) = 4 \cdot 18 = 72\]
\[\boxed{\ \mathbf{516\ (456)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]