\[ 9 \frac{5}{6} = \frac{9 \cdot 6 + 5}{6} = \frac{54 + 5}{6} = \frac{59}{6} \]
\[ 10 - (\frac{59}{6} - z) = 10 - \frac{59}{6} + z \]
\[ 10 = \frac{10 \cdot 6}{6} = \frac{60}{6} \]
\[ \frac{60}{6} - \frac{59}{6} + z = \frac{60 - 59}{6} + z \]
\[ \frac{60 - 59}{6} + z = \frac{1}{6} + z \]
Ответ: 1/6 + z