$$16\frac{4}{9} : 8 = (16:8) + (\frac{4}{9} : 8) = 2 + \frac{4}{9 \cdot 8} = 2 + \frac{4}{72} = 2 + \frac{1}{18} = 2\frac{1}{18}$$
Ответ: $$2\frac{1}{18}$$