Fill in the boxes with the correct number

$\begin{array}{ccccc}& 6& 8& 8& 2\\ +& 2& \boxed{}& 3& 8\\ & \boxed{}& 3& \boxed{}& 0\end{array}$

$319\times 706=$?

Write correct digits in the place of ?.

$$\begin{gathered} 1 3 8 7 0 \\ \underline{- ? ? 3 ?} \\ \underline{ 6 8 ? ?} \end{gathered}$$

Simplify the following numerical expressions.

$249\times 47$

Write correct digits in the place of ?.

$$\begin{gathered} 5 1 7 3 \\ \underline{-? ? 8 8} \\ \underline{ 1 1 ? ?} \end{gathered}$$

Simplify the following numerical expression.

$180\times 345$

Simplify the following numerical expressions.

$3867500-3865347$

Simplify the following numerical expressions.

$48047-29918$