[tex] \frac{5}{33} + \frac{1}{22} = \frac{5 \times 2}{33 \times 2} + \frac{1 \times 3}{22 \times 3} = \frac{10}{66} + \frac{3}{66} = \frac{10 + 3}{66} = \frac{13}{66} [/tex]
