\(M=\dfrac{9}{40}-\dfrac{11}{60}+\dfrac{13}{84}-\dfrac{15}{112}\)
\(M=\left(\dfrac{90}{40}-\dfrac{11}{60}\right)+\left(\dfrac{13}{84}-\dfrac{15}{112}\right)\)
\(M=\dfrac{27}{120}-\dfrac{22}{120}+\dfrac{52}{336}-\dfrac{45}{336}\)
\(M=\dfrac{5}{120}+\dfrac{7}{336}\)
\(M=\dfrac{1}{24}+\dfrac{1}{48}\)
\(M=\dfrac{3}{48}=\dfrac{1}{16}\)
M=\(\dfrac{9}{40}-\dfrac{11}{60}+\dfrac{13}{84}-\dfrac{15}{112}\)
M=\(\dfrac{1}{24}+\dfrac{13}{84}-\dfrac{15}{112}\)
M=\(\dfrac{11}{56}-\dfrac{15}{112}\)
M=\(\dfrac{1}{16}\)