\[\boxed{\mathbf{6.65}}\]
\[\textbf{а)}\ \frac{5}{8} = \frac{10}{16};\]
\[\frac{1}{16};\ \frac{2}{16} = \frac{1}{8};\ \frac{3}{16};\ \frac{4}{16} = \frac{1}{4};\]
\[\ \frac{5}{16};\ \frac{7}{16};\ \frac{8}{16} = \frac{1}{2};\ \frac{9}{16}.\]
\[\textbf{б)}\ \frac{5}{8} = \frac{10}{16};\]
\[\frac{11}{16};\ \frac{12}{16} = \frac{3}{4};\ \frac{13}{16};\ \frac{14}{16} = \frac{7}{8};\ \frac{15}{16}\text{.\ }\]