Tính: 2/3 + 4/5

a) \(\frac{2}{3} + \frac{4}{5} = \frac{{10}}{{15}} + \frac{{12}}{{15}} = \frac{{22}}{{15}}\)

\(\frac{8}{7} + 9 = \frac{8}{7} + \frac{{63}}{7} = \frac{{71}}{7}\)

b) \(\frac{8}{5} - \frac{2}{3} = \frac{{24}}{{15}} - \frac{{10}}{{15}} = \frac{{14}}{{15}}\)

\(7 - \frac{3}{{10}} = \frac{{70}}{{10}} - \frac{3}{{10}} = \frac{{67}}{{10}}\)