Rút gọn:
\(\dfrac{131313}{151515}=\dfrac{13\times10101}{15\times10101};\dfrac{131313}{353535}=\dfrac{13\times10101}{35\times10101}\)
\(\dfrac{131313}{636363}=\dfrac{13\times10101}{63\times10101};\dfrac{131313}{999999}=\dfrac{13\times10101}{99\times10101}\)
\(\Rightarrow\dfrac{131313}{151515}+\dfrac{131313}{353535}+\dfrac{131313}{636363}+\dfrac{131313}{999999}\)
\(=\dfrac{13}{15}+\dfrac{13}{35}+\dfrac{13}{63}+\dfrac{13}{99}\)
\(=\dfrac{3003}{3456}+\dfrac{1287}{3456}+\dfrac{715}{3456}+\dfrac{455}{3456}\)
\(=\dfrac{\left(3003+1287+715+455\right)}{3456}\)
\(=\dfrac{5460}{3456}=\dfrac{52}{33}\)