a, \(=\dfrac{-1+-1.3}{21}=\dfrac{-4}{21}\\ b,=\dfrac{-5.12-1.9}{108}=\dfrac{-69}{108}=-\dfrac{23}{36}\\ c,=\dfrac{37}{5}-\left(-\dfrac{7}{5}\right)=\dfrac{44}{5}\\ d,=\dfrac{4.3-2}{3}=\dfrac{10}{3}\\ e,=-\dfrac{3}{7}+\left(\dfrac{10-4.7}{7}\right)=-\dfrac{3}{7}+-\dfrac{18}{7}=-3\\ f,=\dfrac{1}{15}-\dfrac{-1}{4}+\dfrac{14}{15}+\dfrac{3}{4}-\dfrac{3}{2}=\left(\dfrac{1}{15}+\dfrac{14}{15}\right)+\left(\dfrac{1}{4}+\dfrac{3}{4}\right)-\dfrac{3}{2}=1+1-\dfrac{3}{2}=\dfrac{1}{2}\\ g,-\dfrac{3}{2}.\left(-0,8\right)=-\dfrac{3}{2}.\left(-\dfrac{4}{5}\right)=\dfrac{6}{5}\)
\(h,\left(-\dfrac{1}{5}\right).4\dfrac{1}{2}=\left(-\dfrac{1}{5}\right).\dfrac{9}{2}=-\dfrac{9}{10}\\ i,-3\dfrac{3}{4}:\left(-2,1\right)=-\dfrac{15}{4}.-\dfrac{10}{21}=\dfrac{63}{8}\)
