\(\text{bạn ơi làm đc òi: }\)

\(c\)) \(\left(\dfrac{21}{31}+\dfrac{2013}{6039}\right)-\left(\dfrac{44}{53}-\dfrac{10}{31}\right)-\dfrac{9}{53}\)

\(=\left(\dfrac{21}{31}+\dfrac{11}{31}\right)-\left(\dfrac{44}{53}+\dfrac{9}{53}\right)+\dfrac{1}{3}\)

\(=1-1+\dfrac{1}{3}=0+\dfrac{1}{3}=\dfrac{1}{3}\)