\[\boxed{\text{6.192.}}\]
\[\textbf{а)}\ 7\ 654,4 + (178,27 + 304,16) =\]
\[= 7\ 654,4 + 482,43 = 8\ 136,83\ \]
\[\textbf{б)}\ 36,531 - (17,743 - 0,8) =\]
\[= 36,531 - 16,943 = 19,588\]
\[\textbf{в)}\ 675,4 + (700 - 674,4) =\]
\[= (675,4 - 674,4) + 700 =\]
\[= 1 + 700 = 701\]
\[\textbf{г)}\ (43,76 - 38,45) - 3,76 =\]
\[= (43,76 - 3,76) - 38,45 =\]
\[= 40 - 38,45 = 1,55\]