Given:
[tex]\frac{3}{9}[/tex] and [tex]\frac{1}{2}[/tex]
Finding a common denominator:
9 * 2 = 18
-> If you need to stop here, a common denominator is 18.
Converting [tex]\frac{3}{9}[/tex]:
[tex]\frac{3}{9}[/tex] = [tex]\frac{3*2}{9*2}[/tex] = [tex]\frac{6}{18}[/tex]
Converting [tex]\frac{1}{2}[/tex]:
[tex]\frac{1}{2}[/tex] = [tex]\frac{1*9}{2*9}[/tex] = [tex]\frac{9}{18}[/tex]
-> [tex]\frac{6}{18}[/tex] and [tex]\frac{9}{18}[/tex]