\[\boxed{\mathbf{490}.}\]
\[1)\ 6,53 + (1,095 + 3,47) =\]
\[= (6,53 + 3,47) + 1,095 =\]
\[= 10 + 1,095 = 11,095\]
\[2)\ 18,351 + 1,9 + 1,649 =\]
\[= (18,351 + 1,649) + 1,9 =\]
\[= 20 + 1,9 = 21,9\]