\[\boxed{\mathbf{189.}}\]
\[1)\ 312 + 200 = 512\]
\[312 - 200 = 112\]
\[2)\ 416 + 200 = 616\]
\[416 - 200 = 216\]
\[642 + 300 = 942\]
\[642 - 300 = 342\]
\[527 + 400 = 927\]
\[527 - 400 = 127\]