a) [tex]0.27 = \frac{n}{10^3} \Rightarrow 0,27\cdot10^3 = n \Rightarrow n = 270[/tex]
b) [tex]3,523 = \frac{3523}{10^n} \Rightarrow 10^n = \frac{3523}{3,523} \Rightarrow 10^n = 1000 \Rightarrow n =3[/tex]
c) [tex]3,(3) = \frac{4}{n} \Rightarrow n = \frac{4}{3,(3)} \Rightarrow n = 7[/tex]