Odpowiedź:
[tex]1.\\\\\frac{3}{4}-\frac{1}{3}\cdot\frac{4}{5}+\frac{2}{5}=\frac{3}{4}-\frac{4}{15}+\frac{2}{5}=\frac{45}{60}-\frac{16}{60}+\frac{24}{60}=\frac{29}{60}+\frac{24}{60}=\frac{53}{60}\\\\\\2.\\\\a)\ \ 1\frac{2}{3}+2\frac{3}{4}=1\frac{8}{12}+2\frac{9}{12}=3\frac{17}{12}=4\frac{5}{12}\\\\b)\ \ 4\frac{3}{5}-2\frac{5}{8}=4\frac{24}{40}-2\frac{25}{40}=3\frac{64}{40}-2\frac{25}{40}=1\frac{39}{40}[/tex]
