Aider moi s'il vous plait

[tex]A= \frac{1}{2}+ \frac{3}{4} - \frac{5}{6}\\\\ B= \frac{12}{24}+ \frac{18}{24} - \frac{20}{24}\\\\ A= \frac{10}{24}\\\\ A= \frac{5}{12}\\\\\\\\ B= \frac{3}{4}- \frac{2}{3}\times \frac{15}{8}\\\\ B= \frac{3}{4}- \frac{30}{24}\\\\ B= \frac{18}{24}- \frac{30}{24}\\\\ B= \frac{-12}{24}\\\\ B= \frac{-1}{2}\\\\\\\\ C = ( \frac{2}{5}+ \frac{1}{3}): \frac{2}{3}\\\\ C= ( \frac{6}{15}+ \frac{5}{15}): \frac{2}{3}\\\\ C= \frac{11}{15}: \frac{2}{3}\\\\ [/tex]
[tex]C= \frac{11}{15}\times \frac{3}{2}\\\\ C= \frac{33}{30} [/tex]