\[\boxed{\text{5.339.}}\]
\[\textbf{а)}\ \frac{3}{20} + \frac{7}{20} = \frac{10}{20} = \frac{1}{2}\ \]
\[\textbf{б)}\ \frac{13}{15} - \frac{8}{15} = \frac{5}{15} = \frac{1}{3}\]
\[\textbf{в)}\ \frac{9}{22} + \frac{2}{22} = \frac{11}{22} = \frac{1}{2}\ \]
\[\textbf{г)}\ \frac{29}{36} - \frac{21}{36} = \frac{8}{36} = \frac{2}{9}\text{\ \ }\]