Rút gọn rồi tính

a) \(\frac{8}{{16}} + \frac{5}{9}\)

= \(\frac{1}{2} + \frac{5}{9}\)

= \(\frac{9}{{18}} + \frac{{10}}{{18}}\)

= \(\frac{{19}}{{18}}\)

b) \(\frac{8}{{12}} - \frac{1}{3}\)

= \(\frac{2}{3} - \frac{1}{3}\)

= \(\frac{1}{3}\)

c) \(\frac{{14}}{{20}} - \frac{2}{7}\)

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

= \(\frac{{49}}{{70}} - \frac{{20}}{{70}}\)

= \(\frac{{29}}{{70}}\)

d) \(\frac{{25}}{{30}} + \frac{3}{7}\)

= \(\frac{5}{6} + \frac{3}{7}\)

= \(\frac{{35}}{{42}} + \frac{{18}}{{42}}\)

= \(\frac{{53}}{{42}}\)