Tính các phép tính sau

a) \(\frac{3}{5} + \frac{2}{{15}}\)

= \(\frac{9}{{15}} + \frac{2}{{15}}\)

= \(\frac{{11}}{{15}}\)

b) \(\frac{1}{8} + \frac{3}{7}\)

= \(\frac{7}{{56}} + \frac{{24}}{{56}}\)

= \(\frac{{31}}{{56}}\)

c) \(\frac{9}{{20}} - \frac{1}{6}\)

= \(\frac{{27}}{{60}} - \frac{{10}}{{60}}\)

= \(\frac{{17}}{{60}}\)

d) \(\frac{7}{{10}} - \frac{1}{5}\)

= \(\frac{7}{{10}} - \frac{2}{{10}}\)

= \(\frac{5}{{10}} = \frac{1}{2}\)