16) \(1 \frac{1}{12} : (1 \frac{13}{18} - 2 \frac{5}{9})\)

$$1 \frac{1}{12} : (1 \frac{13}{18} - 2 \frac{5}{9}) = \frac{13}{12} : (\frac{31}{18} - \frac{23}{9}) = \frac{13}{12} : (\frac{31}{18} - \frac{46}{18}) = \frac{13}{12} : (\frac{31 - 46}{18}) = \frac{13}{12} : \frac{-15}{18} = \frac{13}{12} \cdot \frac{18}{-15} = \frac{13 \cdot 18}{12 \cdot (-15)} = \frac{13 \cdot 3}{2 \cdot (-15)} = \frac{39}{-30} = -\frac{13}{10} = -1,3$$