1: \(=\dfrac{35-12}{20}=\dfrac{23}{20}\)
4: \(=8-8\cdot4\cdot2=8-64=-56\)
\(1.\dfrac{7}{4}+\dfrac{-3}{5}=\dfrac{35}{20}-\dfrac{12}{20}=\dfrac{23}{20}\)
\(2.\left(-\dfrac{1}{2}\right)^2.\dfrac{4}{11}+\dfrac{7}{11}.\left(-\dfrac{1}{2}\right)^2=\dfrac{1}{4}.\left(\dfrac{4}{11}+\dfrac{7}{11}\right)=\dfrac{1}{4}.\dfrac{11}{11}=\dfrac{1}{4}\)
\(3.\left(\dfrac{11}{12}:\dfrac{33}{12}\right).\dfrac{3}{5}=\left(\dfrac{11}{12}.\dfrac{12}{33}\right).\dfrac{3}{5}=\dfrac{1}{3}.\dfrac{3}{5}=\dfrac{1}{5}\)
\(4.2^3-8.\left[\left(-2\right)^2:\dfrac{1}{2}\right]=8-8.\left(4:\dfrac{1}{2}\right)=8-8.8=8-64=-56\)
