7.
[tex]a) \ 2\frac{1}{3}+\frac{5}{6}\cdot\frac{3}{5} = 2\frac{1}{3}+\frac{3}{6} = 2\frac{2}{6}+\frac{3}{6} = 2\frac{5}{6}\\\\b) \ 7-\frac{4}{5}:2\frac{1}{2} = 7-\frac{4}{5}:\frac{5}{2} = 7-\frac{4}{5}\cdot\frac{2}{5} = 7-\frac{8}{25} = 6\frac{17}{25}\\\\c) \ 1\frac{1}{4}\cdot1\frac{3}{5}-(0,6-0,55) = \frac{5}{4}\cdot\frac{8}{5}-0,05 = \frac{8}{4}-\frac{5}{100} = \frac{200}{100}-\frac{5}{100} = \frac{195}{100} = 1\frac{95}{100}=1\frac{19}{20}[/tex]
[tex]d) \ 4\frac{1}{2}\cdot\frac{2}{3}-\frac{1}{4} = \frac{9}{2}\cdot\frac{2}{3} =\frac{9}{3}-\frac{1}{4} = 3-\frac{1}{4} = 2\frac{3}{4}[/tex]
6.
2/3 = 0,666 ... okres: 6 krótszy zapis: 0,(6)
1/12 = 0,08333 ... okres: 3 krótszy zapis: 0,08(3)
13/11 = 1,181818 ... okres: 18 krótszy zapis: 1,(18)
