[tex] A = \frac{7}{6} + \frac{5}{4} - \frac{13}{12} = \frac{42}{36} + \frac{9}{36} - \frac{39}{36} = \frac{12}{36} = \frac{1}{3}[/tex]
[tex]B = \frac{5}{11} - \frac{2}{3} + \frac{1}{2} = \frac{30}{66} - \frac{44}{66} + \frac{33}{66} = \frac{19}{66}[/tex]
[tex]C = \frac{1}{3} - \frac{4}{8} - \frac{5}{6} = \frac{8}{24} - \frac{12}{24} - \frac{20}{24} = \frac{-24}{24} = -1[/tex]
[tex]D = \frac{9}{20} + \frac{-2}{5} - \frac{1}{3} = \frac{27}{60} + \frac{-24}{60} - \frac{20}{60} = \frac{-17}{60} [/tex]
