Bài 1:
\(a,\dfrac{1}{12}-\left(-\dfrac{1}{6}-\dfrac{1}{4}\right)\)
\(=\dfrac{1}{12}-\left(\dfrac{-2}{12}-\dfrac{3}{12}\right)\)
\(=\dfrac{1}{12}-\dfrac{-5}{12}\)
\(=\dfrac{1}{12}+\dfrac{5}{12}\)
\(=\dfrac{6}{12}\)
\(=\dfrac{1}{2}\)
\(b,1,5-\dfrac{5}{4}+\left(\dfrac{-7}{3}\right)^0\)
\(=\dfrac{3}{2}-\dfrac{5}{4}+1\)
\(=\dfrac{6}{4}-\dfrac{5}{4}+\dfrac{4}{4}\)
\(=\dfrac{5}{4}\)
\(c,\left(-\dfrac{25}{13}\right)+\left(-\dfrac{9}{17}\right)+\dfrac{12}{13}+\left(-\dfrac{25}{17}\right)\)
\(=\dfrac{-25}{13}-\dfrac{9}{17}+\dfrac{12}{13}-\dfrac{25}{17}\)
\(=\left(\dfrac{-25}{13}+\dfrac{12}{13}\right)-\left(\dfrac{9}{17}+\dfrac{25}{17}\right)\)
\(=\dfrac{-13}{13}-\dfrac{34}{17}\)
\(=\left(-1\right)-2\)
\(=-3\)
\(d,\dfrac{14}{13}+\dfrac{5}{6}+\dfrac{3}{5}-\dfrac{1}{13}+\dfrac{1}{6}+\dfrac{2}{5}\)
\(=\left(\dfrac{14}{13}-\dfrac{1}{13}\right)+\left(\dfrac{5}{6}+\dfrac{1}{6}\right)+\left(\dfrac{3}{5}+\dfrac{2}{5}\right)\)
\(=\dfrac{13}{13}+\dfrac{6}{6}+\dfrac{5}{5}\)
\(=1+1+1\)
\(=3\)
\(e,\dfrac{5}{7}.\left(\dfrac{-3}{11}\right)+\dfrac{5}{7}.\left(\dfrac{-8}{11}\right)+2\dfrac{5}{7}\)
\(=\dfrac{5}{7}.\left(\dfrac{-3}{11}+\dfrac{-8}{11}\right)+\dfrac{19}{7}\)
\(=\dfrac{5}{7}.\dfrac{-11}{11}+\dfrac{19}{7}\)
\(=\dfrac{5}{7}.\left(-1\right)+\dfrac{19}{7}\)
\(=\dfrac{-5}{7}+\dfrac{19}{7}\)
\(=\dfrac{14}{7}=2\)
