\[\boxed{\text{213\ (213).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ 100 + x = 370\]
\[x = 370 - 100\]
\[x = 270.\]
\[2)\ 400 - x = 130\]
\[x = 400 - 130\]
\[3)\ 1 \cdot x = 270\]
\[x = 270\ :1\]