Thực hiện phép tính: a) 12/17 - 2/9 + 5/ 17 - 7/9

a) \[\frac{{12}}{{17}} - \frac{2}{9} + \frac{5}{{17}} - \frac{7}{9}\]\[ = \left( {\frac{{12}}{{17}} + \frac{5}{{17}}} \right) - \left( {\frac{2}{9} + \frac{7}{9}} \right) = 0\]

b) \(\frac{{11}}{3}.\frac{8}{{13}} + \frac{5}{{13}}.\frac{{22}}{6} - \frac{2}{3}\)\( = \frac{{11}}{3}.\frac{8}{{13}} - \frac{5}{{13}}.\frac{{11}}{3} - \frac{2}{3}\)

\( = \frac{{11}}{3}.\left( {\frac{8}{{13}} + \frac{5}{{13}}} \right) - \frac{2}{3} = 3\)

c) \[\frac{5}{3}:\left[ {\left( {5,22 - 0,02} \right).\frac{{\sqrt {25} }}{{26}}} \right] - \left| { - \frac{1}{2}} \right|\]

\[ = \frac{5}{3}:\left( {5,2.\frac{5}{{26}}} \right) - \frac{1}{2}\]\[ = \frac{5}{3}:1 - \frac{1}{2} = \frac{7}{6}\].