Tính.

\(\frac{5}{9}\) + \(\frac{{24}}{{45}}\) = \(\frac{{25}}{{45}}\) + \(\frac{{24}}{{45}}\) = \(\frac{{49}}{{45}}\)

\(\frac{{45}}{{48}}\) – \(\frac{7}{8}\) = \(\frac{{45}}{{48}}\) – \(\frac{{42}}{{48}}\) = \(\frac{3}{{48}}\) = \(\frac{1}{{16}}\)

\(\frac{{45}}{4}\) × \(\frac{{24}}{9}\) = 30

\(\frac{{25}}{{63}}\) : \(\frac{5}{7}\) = \(\frac{{25}}{{63}}\)× \(\frac{7}{5}\) = \(\frac{5}{9}\)