1 1/2 = 1,5 = 15/10=3/2 (3/2)/3 = 1/2 1/2 von 100 = 1/2 * 100 = 50
$${\frac{\left({\mathtt{1}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{1}}}{{\mathtt{2}}}}\right)}{{\mathtt{3}}}}{\mathtt{\,\times\,}}{\mathtt{100}} = {\mathtt{50}}$$
Zufrieden ?
Gruß radix 
!
