55*7/11-55*6/11; 12/19*23/15-12/19*4/15; 47/11*1/2-25/11*1/2

1) [latex]55* \frac{7}{11}-55* \frac{6}{11}=5*7-5*6=35-30=5 [/latex] 2) [latex]\frac{12}{19}*\frac{23}{15}-\frac{12}{19}*\frac{4}{15}=\frac{4}{19}*\frac{23}{5}-\frac{4}{19}*\frac{4}{5}=\frac{92}{95}-\frac{16}{95}=\frac{76}{95}=0,8[/latex] 3) [latex]\frac{47}{11}*\frac{1}{2}-\frac{25}{11}*\frac{1}{2}=\frac{47}{22}-\frac{25}{22}=\frac{47-25}{22}= \frac{22}{22}=1 [/latex]