Use "PEMDAS"
First we'll add then subtract
[tex] \frac{1}{2} + \frac{1}{3} = \frac{2}{6} + \frac{2}{6} = \frac{4}{6}= \frac{2}{3} [/tex]
[tex] \frac{2}{3} - \frac{1}{4} = \frac{8}{12} - \frac{3}{12} = \frac{5}{12} [/tex]
[tex] \frac{1}{2} + \frac{1}{3} - \frac{1}{4} = \frac{5}{12} [/tex]
