[tex]\frac{5}{10}*\frac{10}{40}=\frac{50}{400}[/tex]
[tex]\frac{2}{8}*\frac{2}{4}=\frac{4}{32}[/tex]
[tex]\frac{1}{4}*\frac{1}{2}=\frac{1}{8}[/tex]
[tex]\frac{1}{8}[/tex] is obtained by multiplying [tex]\frac{1}{2}[/tex] and [tex]\frac{1}{4}[/tex]
You basically create equivelant fractions for both 1/2 and 1/4 and multiply by each other. This way you get the same result always.
