$$\frac{17r^4s^3}{54t^5}\;\cdot\;\frac{24st^2}{85r^2}$$

17r4s324st254t585r2=\dfrac{17r^4s^324st^2}{54t^585r^2}=
Klammere r2r^2 aus.
=r2(17r2s324st2)54t585r2=\dfrac{r^2(17r^2s^324st^2)}{54t^585r^2}
Kürze mit r2r^2.
=17r2s324st254t585=\dfrac{17r^2s^324st^2}{54t^585}
Kürze mit t2t^2.
=17r2s324s54t385=\dfrac{17r^2s^3 24s}{54t^3 85}
=408r2s44590t3=\dfrac{408r^2s^4}{4590t^3}
  :102\vert\;:102
=4r2s445t3=\dfrac{4r^2s^4}{45t^3}