[tex] \frac{1}{18 } + \frac{1}{9 } + \frac{1}{6} = \frac{1}{18} + \frac{2}{18} + \frac{3}{18} = \frac{6}{18} = \frac{1}{3} [/tex]
[tex] \frac{7}{36} - \frac{1}{18} + \frac{3}{4} = \frac{7}{36} - \frac{2}{36} + \frac{27}{36} = \frac{32}{36} = \frac{8}{9} [/tex]
