(\frac{3}{4}-\frac{1}{5}):\frac{1}{2}=(\frac{15}{20}-\frac{4}{20}):\frac{1}{2}=\frac{11}{20}):\frac{1}{2}=\frac{11}{20})*\frac{2}{1}=\frac{11}{10}=1,1
3,2:(0,8-\frac{2}{5})=3,2:(0,8-0,4)=3,2-0,4=2,8
\frac{2}{3}*(\frac{1}{2}-\frac{1}{6})=\frac{2}{3}*(\frac{3}{6}-\frac{1}{6})=\frac{2}{3}*\frac{2}{6}=\frac{2}{3}*\frac{1}{3}=\frac{2}{9}
\frac{4}{8}+\frac{1}{3}*(1,2-0,6)=\frac{4}{8}+\frac{1}{3}*0,6=\frac{4}{8}+\frac{1}{3}*\frac{6}{10}=\frac{4}{8}+\frac{1}{3}*\frac{3}{5}=\frac{4}{8}+\frac{1}{5}=\frac{20}{40}+\frac{8}{40}=\frac{28}{40}=0,7
(1-\frac{7}{9})*(5,2-0,7)=\frac{2}{9}*4,5=\frac{2}{9}*\frac{45}{10}=\frac{5}{5}=1
123:10+0,2*6,1=12,3+1,22=13,52
(6,5-4,7):(4-2\frac{1}{5})=1,8:1\frac{4}{5}=1,8:1,8=1
(1,5-1\frac{1}{3})*2\frac{2}{5}-0,1=(1\frac{1}{2}-1\frac{1}{3})*2\frac{2}{5}-0,1=(1\frac{3}{6}-1\frac{2}{6})*2\frac{2}{5}-0,1=\frac{1}{6}*2\frac{2}{5}-0,1=\frac{1}{6}*\frac{12}{5}-0,1=\frac{2}{5}-0,1=0,4-0,1=0,3
(6,25-2\frac{1}{2}):2\frac{1}{7}-1=(6,25-2,5):2\frac{1}{7}-1=3,75:\frac{15}{7}-1=3\frac{3}{4}*\frac{7}{15}-1=\frac{15}{4}*\frac{7}{15}-1=\frac{7}{4}-1=1\frac{3}{4}-1=\frac{3}{4}