2. Вычислите: $$\frac{27}{40} : 18 + \frac{9}{16}$$.

Сначала выполним деление, представив 18 как $$\frac{18}{1}$$, затем сложение: \(\begin{align*}\) \(\frac{27}{40}\) : 18 + \(\frac{9}{16}\) &= \(\frac{27}{40}\) : \(\frac{18}{1}\) + \(\frac{9}{16}\) \\ &= \(\frac{27}{40}\) \(\cdot\) \(\frac{1}{18}\) + \(\frac{9}{16}\) \\ &= \(\frac{27}{40 \cdot 18}\) + \(\frac{9}{16}\) \\ &= \(\frac{3}{40 \cdot 2}\) + \(\frac{9}{16}\) \\ &= \(\frac{3}{80}\) + \(\frac{9}{16}\) \\ &= \(\frac{3}{80}\) + \(\frac{9 \cdot 5}{16 \cdot 5}\) \\ &= \(\frac{3}{80}\) + \(\frac{45}{80}\) \\ &= \(\frac{3+45}{80}\) \\ &= \(\frac{48}{80}\) \\ &= \(\frac{6}{10}\) = \(\frac{3}{5}\) = 0.6 \(\end{align*}\) **Ответ: 0.6**