Odpowiedź:
[tex]( \frac{2}{3} + \frac{5}{6} ) \div 3 - ( \frac{7}{9} - \frac{1}{2} ) =( \frac{4}{6} + \frac{5}{6} ) \div 3 - ( \frac{14}{18} - \frac{9}{18} ) = \frac{9}{6} \div 3 - \frac{5}{18} = \frac{1}{2} - \frac{5}{18} = \frac{9}{18} - \frac{5}{18} = \frac{4}{18} = \frac{2}{9} [/tex]
