\[\boxed{\mathbf{2.}\mathbf{206}}\]
\[\textbf{а)}\ 36,42 \cdot 0,1 - 0,996 =\]
\[= 3,642 - 0,996 = 2,646\]
\[69,77 \cdot 5,8 - 69,67 \cdot 5,8 =\]
\[= 5,8 \cdot (69,77 - 69,67) =\]
\[= 5,8 \cdot 0,1 = 0,58\]
\[0,58 + 0,42 = 1\]
\[1\ :0,4 = 10\ :4 = 2,5\]
\[= 148,96 - 5,11 = 143,85\]
\[12,93 + 65,47 = 78,4\]
\(0,317 + 1,583 = 1,9\)
\[39\ 000\ :65 = 600\]
\[600 + 138 = 738\]