Đáp án:

 $a) \dfrac{29}{5}\\
b) -15\\
c) \dfrac{1}{2}\\
d) \dfrac{-161}{60}$

Giải thích các bước giải:

 $a) 4\dfrac{11}{23}+3\dfrac{4}{5}-2\dfrac{11}{23}\\
=\dfrac{103}{23}+\dfrac{19}{5}-\dfrac{57}{23}\\
=\left ( \dfrac{103}{23}-\dfrac{57}{23} \right )+\dfrac{19}{5}\\
=\dfrac{46}{23}+\dfrac{19}{5}\\
=\dfrac{2.23}{23}+\dfrac{19}{5}\\
=2+\dfrac{19}{5}\\
=\dfrac{10}{5}+\dfrac{19}{5}\\
=\dfrac{29}{5}\\
b) 11\dfrac{4}{5}-\left ( 17\dfrac{3}{4}+11\dfrac{4}{5} \right )+2\dfrac{3}{4}\\
=11\dfrac{4}{5}-17\dfrac{3}{4}-11\dfrac{4}{5} +2\dfrac{3}{4}\\
=-17\dfrac{3}{4}+2\dfrac{3}{4}\\
=-\dfrac{71}{4}+\dfrac{11}{4}\\
=\dfrac{-60}{4}\\
=-15\\
c) \dfrac{-27}{26}--\dfrac{5}{21}+\dfrac{1}{26}+\dfrac{16}{21}+\dfrac{50}{100}\\
=\left ( \dfrac{-27}{26}+\dfrac{1}{26} \right )+\left ( \dfrac{5}{21}+\dfrac{16}{21} \right )+\dfrac{50}{100}\\
=\dfrac{-26}{26}+\dfrac{21}{21}+\dfrac{1}{2}\\
=-1+1+\dfrac{1}{2}=\dfrac{1}{2}\\
d) -2\dfrac{2}{3}+0,2-1,75+\dfrac{5}{6}+0,7\\
=\dfrac{-8}{3}+\dfrac{2}{10}-\dfrac{7}{4}+\dfrac{5}{6}+\dfrac{7}{10}\\
=\dfrac{-8}{3}-\dfrac{7}{4}+\dfrac{5}{6}+\left (\dfrac{2}{10}+\dfrac{7}{10}  \right )\\
=\dfrac{-8}{3}-\dfrac{7}{4}+\dfrac{5}{6}+\dfrac{9}{10}\\
=\dfrac{(-8).20}{60}-\dfrac{7.15}{60}+\dfrac{5.10}{60}+\dfrac{9.6}{60}\\
=\dfrac{-160-105+50+54}{60}\\
=\dfrac{-161}{60}$