\[\boxed{\text{5.282.}}\]
\[\textbf{а)}\ 14\frac{9}{13} - 1\frac{5}{13} + 12\frac{11}{13} =\]
\[= 13\frac{4}{13} + 12\frac{11}{13} = 25\frac{15}{13} =\]
\[= 26\frac{2}{13}\ \]
\[\textbf{б)}\ 7\frac{24}{25} - 3\frac{12}{25} - 1\frac{7}{25} =\]
\[= 4\frac{12}{25} - 1\frac{7}{25} = 3\frac{5}{25}\ \]
\[\textbf{в)}\ 17\frac{7}{40} + 3\frac{9}{40} + \frac{17}{40} =\]
\[= 20\frac{16}{40} + \frac{17}{40} = 20\frac{33}{40}\]
\[17\frac{7}{40} + 3\frac{9}{40} - \frac{17}{40} =\]
\[= 20\frac{16}{40} - \frac{17}{40} = 19\frac{56}{40} - \frac{17}{40} =\]
\[= 19\frac{39}{40}\ \]
\[\textbf{г)}\ 23\frac{15}{49} - 13\frac{19}{49} - 1\frac{30}{49} =\]
\[= 22\frac{64}{49} - 13\frac{19}{49} - 1\frac{30}{49} =\]
\[= 9\frac{45}{49} - 1\frac{30}{49} = 8\frac{15}{49}\]