[tex]1)\\\\(6,25-2\frac{1}{2}):2\frac{1}{7}-1= (6 \frac{25}{100}-2\frac{1}{2}): \frac{15}{7}-1=(6 \frac{1}{4}-2\frac{2}{4})* \frac{7}{15}-1= \\\\=(5 \frac{5}{4}-2\frac{2}{4})* \frac{7}{15}-1= 3\frac{3}{4}*\frac{7}{15}-1=\frac{\not{15}^1}{4}*\frac{7}{\not{15}^1}-1= \frac{7}{4}-1=1\frac{3}{4}-1=\frac{3}{4}[/tex]
[tex]2)\\\\(14*\frac{ 81-17 }{21} ) :\frac{8}{3}=(\not{14}^2*\frac{ 64 }{\not{21}^3} ) *\frac{3}{8}=\frac{\not{128}^{16}}{\not{3}^1}*\frac{\not{3}^1}{\not{8}^1}=16[/tex]
[tex]3)\\\\ \frac{ \frac{2}{3} + \frac{2}{4} -0,5}{(0,2+0,8*(- \frac{1}{8})} = \frac{ \frac{2}{3} + \frac{2}{4} - \frac{5}{10}}{ \frac{2}{10}+\frac{\not{8}^1}{10} *(- \frac{1}{\not{8}^1} )} = \frac{ \frac{2}{3} + \frac{2}{4} - \frac{1}{2}}{ \frac{2}{10}-\frac{1}{10} } =\frac{ \frac{8}{12} + \frac{6}{12} - \frac{6}{12}}{ \frac{2}{10}-\frac{1}{10} } = \frac{\frac{8}{12}}{\frac{1}{10}} = \\\\ =\frac{\frac{2}{3}}{\frac{1}{10}} = \frac{2}{3}:\frac{1}{10}=\frac{2}{3}*\frac{10}{1}=\frac{20}{3}=6\frac{2}{3}[/tex]
