2: \(\left(\dfrac{3}{4}-\dfrac{5}{6}\right)^2=\left(\dfrac{9}{12}-\dfrac{10}{12}\right)^2=\left(-\dfrac{1}{12}\right)^2=\dfrac{1}{144}\)
4: \(-\dfrac{2}{5}:1\dfrac{1}{3}-\left(\dfrac{1}{2}\right)^2\)
\(=-\dfrac{2}{5}:\dfrac{4}{3}-\dfrac{1}{4}\)
\(=-\dfrac{2}{5}\cdot\dfrac{3}{4}-\dfrac{1}{4}=\dfrac{-3}{10}-\dfrac{1}{4}=\dfrac{-6}{20}-\dfrac{5}{20}=-\dfrac{11}{20}\)
6: \(\left(1+\dfrac{2}{3}-\dfrac{1}{4}\right)\cdot\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2\)
\(=\left(\dfrac{12}{12}+\dfrac{8}{12}-\dfrac{3}{12}\right)\cdot\left(\dfrac{16}{20}-\dfrac{15}{20}\right)^2\)
\(=\dfrac{17}{12}\cdot\left(\dfrac{1}{20}\right)^2=\dfrac{17}{12}\cdot\dfrac{1}{400}=\dfrac{17}{4800}\)
8: \(\left(-\dfrac{2}{3}\right)^2:\left(\dfrac{7}{18}+\dfrac{2}{9}-\dfrac{1}{2}\right)\)
\(=\dfrac{4}{9}:\left(\dfrac{7}{18}+\dfrac{4}{18}-\dfrac{9}{18}\right)\)
\(=\dfrac{4}{9}:\dfrac{2}{18}=\dfrac{4}{9}\cdot9=4\)
10: \(\left(\dfrac{6}{5}\right)^{2013}\cdot\left(\dfrac{5}{6}\right)^{2013}+\left(\dfrac{2012}{2013}\right)^0\)
\(=\left(\dfrac{6}{5}\cdot\dfrac{5}{6}\right)^{2013}+1=1+1=2\)
12: \(\left(-\dfrac{2}{7}\right)^2\cdot343-\left(-\dfrac{2013}{2014}\right)^0+64\cdot\left(\dfrac{1}{2}\right)^3\)
\(=\dfrac{4}{49}\cdot343-1+64\cdot\dfrac{1}{8}\)
\(=28-1+8=36-1=35\)
