\[\boxed{\mathbf{444}.}\]
\[1)\ x + 2,477 = 3,42\]
\[x = 3,42 - 2,477\]
\[x = 0,943.\]
\[2)\ 100 - x = 6,19\]
\[x = 100 - 6,19\]
\[x = 93,81.\]
\[3)\ x - 19,4 = 1,6\]
\[x = 1,6 + 19,4\]
\[x = 21.\]