a: \(-\dfrac{4}{7}-\dfrac{14}{56}+\dfrac{4}{7}=\left(-\dfrac{4}{7}+\dfrac{4}{7}\right)-\dfrac{14}{56}=-\dfrac{1}{4}\)
c: \(-\left(-\dfrac{31}{32}-\dfrac{7}{15}\right)+\left(-\dfrac{15}{32}-\dfrac{7}{15}\right)\)
\(=\dfrac{31}{32}+\dfrac{7}{15}-\dfrac{15}{32}-\dfrac{7}{15}\)
\(=\dfrac{31}{32}-\dfrac{15}{32}=\dfrac{16}{32}=\dfrac{1}{2}\)
e: \(\left(\dfrac{5}{2}\right)^3\cdot\left(\dfrac{3}{8}\right)^0:\left(\dfrac{4}{25}\right)^2\)
\(=\dfrac{125}{8}\cdot1:\dfrac{16}{625}\)
\(=\dfrac{125}{8}\cdot\dfrac{625}{16}=\dfrac{78125}{128}\)
g: \(\left(-\dfrac{13}{7}-\dfrac{4}{9}\right)-\left(-\dfrac{10}{7}-\dfrac{4}{9}\right)\)
\(=-\dfrac{13}{7}-\dfrac{4}{9}+\dfrac{10}{7}+\dfrac{4}{9}\)
\(=-\dfrac{13}{7}+\dfrac{10}{7}=-\dfrac{3}{7}\)
i: \(\dfrac{-11}{24}:\dfrac{17}{23}-\dfrac{11}{24}:\dfrac{17}{11}-\dfrac{1}{12}\)
\(=-\dfrac{11}{24}\cdot\dfrac{13}{17}-\dfrac{11}{24}\cdot\dfrac{11}{17}-\dfrac{1}{12}\)
\(=-\dfrac{11}{24}\left(\dfrac{13}{17}+\dfrac{11}{17}\right)-\dfrac{1}{12}\)
\(=-\dfrac{11}{24}\cdot\dfrac{24}{17}-\dfrac{1}{12}=\dfrac{-11}{17}-\dfrac{1}{12}=\dfrac{-132-17}{17\cdot12}=\dfrac{-149}{204}\)
b: \(\dfrac{12}{60}+\left(-\dfrac{1}{5}-2,75\right)-0,25\)
\(=\dfrac{1}{5}-\dfrac{1}{5}-2,75-0,25\)
=-2,75-0,25
=-3
d: \(\dfrac{9}{10}\cdot\dfrac{23}{11}-\dfrac{1}{11}\cdot\dfrac{9}{10}-\dfrac{9}{10}\)
\(=\dfrac{9}{10}\left(\dfrac{23}{11}-\dfrac{1}{11}-1\right)\)
\(=\dfrac{9}{10}\left(\dfrac{22}{11}-1\right)=\dfrac{9}{10}\)
f: \(\left(\dfrac{1}{2}\right)^2\cdot10-2^2\cdot\dfrac{1}{4}+1^{2015}\)
\(=\dfrac{1}{4}\cdot10-4\cdot\dfrac{1}{4}+1\)
\(=\dfrac{5}{2}-1+1=\dfrac{5}{2}\)
h: \(1\dfrac{4}{27}+\dfrac{8}{23}-\dfrac{4}{27}+0,7+\dfrac{15}{23}\)
\(=\left(1+\dfrac{4}{27}-\dfrac{4}{27}\right)+\left(\dfrac{8}{23}+\dfrac{15}{23}\right)+0,7\)
=1+1+0,7
=2,7
k: \(\dfrac{7}{18}\cdot\left(-\dfrac{15}{19}\right)+\dfrac{21}{19}\cdot\dfrac{-7}{18}\)
\(=\dfrac{7}{18}\left(-\dfrac{15}{19}-\dfrac{21}{19}\right)\)
\(=\dfrac{7}{18}\cdot\dfrac{-36}{19}=\dfrac{7\cdot\left(-2\right)}{19}=-\dfrac{14}{19}\)
