\[\boxed{\mathbf{1}\mathbf{.79}}\]
\[1)\ 5488 - 66 \cdot 83 =\]
\[= 5488 - 5478 = 10\]

\[2)\ (2823 - 2319) \cdot 23 =\]
\[= 11\ 592\]

\[3)\ 45 \cdot (1238 - 148) = 49\ 050\]

\[4)\ 21 \cdot 106 - 106 =\]
\[= 106 \cdot (21 - 1) = 106 \cdot 20 =\]
\[= 2\ 120\]