Răspuns:
[tex]a = 1 - \frac{1}{2} = \frac{2}{2} - \frac{1}{2} = \frac{1}{2} \\ b = 1 - \frac{2}{3} = \frac{3}{3} - \frac{2}{3} = \frac{1}{3} \\ c = 1 - \frac{5}{6} = \frac{6}{6} - \frac{5}{6} = \frac{1}{6} \\ a + b + c = \frac{1}{2} + \frac{1}{3} + \frac{1}{6} = \frac{3}{6} + \frac{2}{6} + \frac{1}{6} = \frac{6}{6} = 1 \\ a - b + c = \frac{1}{2} - \frac{1}{3} + \frac{1}{6} = \frac{3}{6} - \frac{2}{6} + \frac{1}{6} = \frac{2}{6} = \frac{1}{3} \\ a + b - c = \frac{1}{2} + \frac{1}{3} - \frac{1}{6} = \frac{3}{6} + \frac{2}{6} - \frac{1}{6} = \frac{4}{6} = \frac{2}{3} \\ a - b - c = \frac{1}{2} - \frac{1}{3} - \frac{1}{6} = \frac{3}{6} - \frac{2}{6} - \frac{1}{6} = \frac{0}{6} = 0[/tex]
