Bài 1:
a) \(\dfrac{-1}{12}-\left(2\dfrac{5}{8}-\dfrac{1}{3}\right)=\dfrac{-1}{12}-\left(\dfrac{21}{8}-\dfrac{1}{3}\right)=\dfrac{-1}{12}-\dfrac{55}{24}=-\dfrac{19}{8}\)
b) \(-1.75-\left(-\dfrac{1}{9}-2\dfrac{1}{18}\right)=-\dfrac{7}{4}+\dfrac{1}{9}+2\dfrac{1}{18}=-\dfrac{7}{4}+\dfrac{1}{9}+\dfrac{37}{18}=\dfrac{5}{12}\)
c) \(\dfrac{2}{5}+\left(-\dfrac{4}{3}\right)+\left(-\dfrac{1}{2}\right)=\dfrac{2}{5}-\dfrac{4}{3}-\dfrac{1}{2}=-\dfrac{43}{30}\)
d) \(\dfrac{3}{12}-\left(\dfrac{6}{15}-\dfrac{3}{10}\right)=\dfrac{3}{12}-\dfrac{6}{15}+\dfrac{3}{10}=\dfrac{3}{20}\)
e) \(\left(8\dfrac{5}{11}+3\dfrac{5}{8}\right)-3\dfrac{5}{11}=\left(\dfrac{93}{11}+\dfrac{29}{8}\right)-\dfrac{38}{11}=\dfrac{69}{8}\)
f) \(\dfrac{4}{9}:\left(-\dfrac{1}{7}\right)+6\dfrac{5}{9}:\left(-\dfrac{1}{7}\right)=\left(\dfrac{4}{9}+6\dfrac{5}{9}\right):\left(-\dfrac{1}{7}\right)=7.\left(-7\right)=-49\)
g) \(\dfrac{-1}{4}.13\dfrac{9}{11}-0,25.6\dfrac{2}{11}=\dfrac{-1}{4}.\dfrac{152}{11}-\dfrac{1}{4}.\dfrac{68}{11}=\dfrac{-1}{4}\left(\dfrac{152}{11}+\dfrac{68}{11}\right)=-5\)
h) \(5\dfrac{27}{5}+\dfrac{27}{23}+0.5-\dfrac{5}{27}+\dfrac{16}{23}=\dfrac{52}{5}+\dfrac{27}{23}+\dfrac{1}{2}-\dfrac{5}{27}+\dfrac{16}{23}=\dfrac{78149}{6210}\)
i) \(\dfrac{3}{8}.27\dfrac{1}{5}-51\dfrac{1}{5}.\dfrac{3}{8}+19=\dfrac{3}{8}\left(27\dfrac{1}{5}-51\dfrac{1}{5}\right)+19=\dfrac{3}{8}.\left(-24\right)+19=10\)
Bài 3:
a) \(\left(0,125\right).\left(-3,7\right).\left(-2\right)^3=\dfrac{1}{8}.\left(-8\right).\left(-3,7\right)=-1.\left(-3,7\right)=3,7\)
b) \(\sqrt{36}.\sqrt{\dfrac{25}{16}}+\dfrac{1}{4}=6.\dfrac{5}{4}+\dfrac{1}{4}=\dfrac{30}{4}+\dfrac{1}{4}=\dfrac{31}{4}=7.75\)
c) \(\sqrt{\dfrac{4}{81}}:\sqrt{\dfrac{25}{81}}-1\dfrac{2}{5}=\dfrac{2}{9}:\dfrac{5}{9}-\dfrac{7}{5}=\dfrac{2}{5}-\dfrac{7}{5}=-\dfrac{5}{5}=-1\)
d) \(0,1.\sqrt{225}.\sqrt{\dfrac{1}{4}}=\dfrac{1}{10}.\dfrac{1}{2}.15=\dfrac{15}{20}=\dfrac{3}{4}=0.75\)