Вычислите: 19/56+(21/56-12/56)-16/56.

\[\frac{19}{56} + \left( \frac{21}{56} - \frac{12}{56} \right) - \frac{16}{56} =\]

\[= \frac{19}{56} + \frac{9}{56} - \frac{16}{56} = \frac{12}{56} = \frac{3}{14}.\]