TeX source:
\begin{array}{rclcl} 60 \,\% &\widehat{=}& 330 \;\text{Hühner} \cr\cr 1 \;\% &\widehat{=}& \dfrac{330}{60} \;\text{Hühner} \cr\cr 100 \,\% &\widehat{=}& \dfrac{100 \cdot 330\;\text{Hühner}}{60} &=& 550 \;\text{Hühner} \end{array}