[tex]\frac{1}{2}-\frac{1}{10}[/tex]
We must write both fractions in a common denominator.
Since 10/2 = 5, we can multiply the numerator and the denominator of the first fraction by 5 have both fractions with the same denominator:
[tex]\frac{5}{10}-\frac{1}{10}=\frac{4}{10}=\frac{2}{5}[/tex]
