tính nhanh
a, \(\dfrac{\dfrac{2}{3}-\dfrac{2}{5}+\dfrac{2}{10}}{\dfrac{8}{2}-\dfrac{8}{5}+\dfrac{8}{10}}+\dfrac{1}{2}\)
b, \(\dfrac{\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{10}}{\dfrac{6}{3}-\dfrac{6}{5}+\dfrac{6}{10}}+\dfrac{5}{6}\)
c, \(\dfrac{\dfrac{1}{2021}+\dfrac{1}{2022}-\dfrac{1}{2023}}{\dfrac{5}{2021}+\dfrac{5}{2022}-\dfrac{5}{2023}}-\dfrac{6}{5}\)
d, \(\dfrac{\dfrac{1}{2}.\dfrac{5}{17}-\dfrac{13}{14}.\dfrac{5}{17}+\dfrac{15}{238}}{\dfrac{-20}{68}+\dfrac{26}{14}.\dfrac{5}{17}-\dfrac{15}{119}}\)
e,\(\dfrac{\dfrac{1}{29}.\dfrac{3}{2}-\dfrac{26}{11}.\dfrac{3}{23}+\dfrac{9}{238}}{\dfrac{-3}{29}+\dfrac{13}{11}.\dfrac{3}{23}-\dfrac{9}{119}}\)
a) \(\dfrac{\dfrac{2}{3}-\dfrac{2}{5}+\dfrac{2}{10}}{\dfrac{8}{3}-\dfrac{8}{5}+\dfrac{8}{10}}=\dfrac{2\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{10}\right)}{8\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{10}\right)}=\dfrac{2}{8}=4\) (sửa)
b) \(\dfrac{\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{10}}{\dfrac{6}{3}-\dfrac{6}{5}+\dfrac{6}{10}}=\dfrac{\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{10}}{6\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{10}\right)}=\dfrac{1}{6}\)
c)
\(\dfrac{\dfrac{1}{2021}+\dfrac{1}{2022}-\dfrac{1}{2023}}{\dfrac{5}{2021}+\dfrac{5}{2022}-\dfrac{5}{2023}}-\dfrac{6}{5}=\dfrac{\dfrac{1}{2021}+\dfrac{1}{2022}-\dfrac{1}{2023}}{5\left(\dfrac{1}{2021}+\dfrac{1}{2022}-\dfrac{1}{2023}\right)}-\dfrac{6}{5}\\ =\dfrac{1}{5}-\dfrac{6}{5}=-\dfrac{5}{5}=-1\)
