i: \(\dfrac{-1}{2}+\dfrac{3}{7}-\dfrac{1}{9}-\dfrac{7}{18}+\dfrac{4}{7}\)
\(=\left(-\dfrac{1}{2}-\dfrac{1}{9}-\dfrac{7}{18}\right)+\left(\dfrac{3}{7}+\dfrac{4}{7}\right)\)
\(=\dfrac{-9-2-7}{18}+\dfrac{7}{7}\)
\(=-\dfrac{18}{18}+\dfrac{7}{7}=-1+1=0\)
k: \(\dfrac{-5}{10}+\dfrac{12}{28}-\dfrac{3}{27}-\dfrac{7}{18}+\dfrac{20}{35}\)
\(=\dfrac{-5}{10}-\dfrac{7}{18}-\dfrac{3}{27}+\dfrac{3}{7}+\dfrac{4}{7}\)
\(=-\dfrac{1}{2}-\dfrac{7}{18}-\dfrac{1}{9}+1\)
\(=\dfrac{-9-7-2}{18}+1=-\dfrac{18}{18}+1=-1+1=0\)
l: \(A=\dfrac{2}{13}\cdot\dfrac{5}{9}+\dfrac{2}{13}\cdot\dfrac{4}{9}+\dfrac{11}{13}\)
\(=\dfrac{2}{13}\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\dfrac{11}{13}\)
\(=\dfrac{2}{3}+\dfrac{11}{13}=\dfrac{13}{13}=1\)
m: \(B=\dfrac{1}{10}\cdot\dfrac{4}{11}+\dfrac{1}{10}\cdot\dfrac{8}{11}-\dfrac{1}{10}\)
\(=\dfrac{1}{10}\left(\dfrac{4}{11}+\dfrac{8}{11}-1\right)\)
\(=\dfrac{1}{10}\cdot\dfrac{1}{11}=\dfrac{1}{110}\)
