a]
[tex]\dfrac{1}{8}=\dfrac{1\cdot125}{8\cdot125}=\dfrac{125}{1000}=\huge\boxed{\boxed{0,125}}[/tex]
b]
[tex]\dfrac{19}{20}=\dfrac{19\cdot5}{20\cdot5}=\dfrac{95}{100}=\huge\boxed{\boxed{0,95}}[/tex]
c]
[tex]\dfrac{23}{25}=\dfrac{23\cdot4}{25\cdot4}=\dfrac{92}{100}=\huge\boxed{\boxed{0,92}}[/tex]