3/7 . (-2/5) . 2 1/3 . 20 19/72
= -6/35 . 7/3 . 1459/72
= -2/5 . 1459/72
= -1459/180
\(M=\dfrac{3}{7}\left(-\dfrac{2}{5}\right).20+\dfrac{19}{72}.2+\left(\dfrac{1}{3}\right)\)
\(=-\dfrac{6}{35}.20+\dfrac{19}{36}+\dfrac{1}{3}\)
\(=-\dfrac{24}{7}+\dfrac{19}{36}+\dfrac{1}{3}\)
\(=-\dfrac{647}{252}\)