Odpowiedź:
[tex] \frac{2}{5} + 0.3 + (0.8 - \frac{1}{2} ) = \frac{2}{5} + \frac{3}{10} + ( \frac{8}{10} - \frac{1}{2} ) = \frac{4}{10} + \frac{3}{10} + ( \frac{8}{10} - \frac{5}{10} ) = \frac{4}{10} + \frac{3}{10} + \frac{3}{10} = \frac{10}{10} = 1[/tex]
