[tex]3 \frac{1}{8}-0,2=3\frac{1}{8}-\frac{2}{10}=3\frac{5}{40}-\frac{8}{40}=2\frac{45}{40}-\frac{8}{40} =2\frac{37}{40} \\\\\\17\frac{3}{4}+1,7= 17\frac{3}{4}+1\frac{7}{10} =17\frac{15}{20}+1\frac{14}{20}=17\frac{29}{20}=18\frac{9}{20}[/tex]
