Заполните один пропуск!

Решите задачу:

$\frac{2}{15}\cdot \frac{5}{6}=\frac{2\cdot 5}{(5\cdot 3)\cdot (2\cdot 3)}=\frac{1}{9}\\\\\frac{1}{9}+x=y\\\\y-\frac{1}{16}=z\\\\z:1\frac{1}{4}=\frac{1}{12}\; \; \to \; \; z=\frac{1}{12}\cdot \frac{5}{4}=\frac{5}{48}\; \; \Rightarrow \\\\y-\frac{1}{16}=\frac{5}{48}\; \; \to \; \; y=\frac{5}{48}+\frac{1}{16}=\frac{5+3}{48}=\frac{8}{48}=\frac{1}{6}\; \; \Rightarrow \\\\\frac{1}{9}+x=\frac{1}{6}\; \; \to \; \; x=\frac{1}{6}-\frac{1}{9}=\frac{3-2}{18}=\frac{1}{18}$