a) Ta có :
\(\dfrac{5}{9} : \dfrac{11}{24}\) \(=\dfrac{5}{9} \times \dfrac{24}{11}\) \(=\dfrac{5\times 24}{9 \times 11}\)
\(= \dfrac{5\times 8 \times 3}{3 \times 3\times 11} = \dfrac{40}{33} > 1\)
Do đó \(\dfrac{5}{9} > \dfrac{11}{24}.\)
b) Chọn phân số trung gian là \(\dfrac{13}{23}\)
Ta có : \(\dfrac{13}{27} < \dfrac{13}{23}\) ; \(\dfrac{13}{23 } < \dfrac{17}{23}\)
Do đó \(\dfrac{13}{27} < \dfrac{13}{23} <\dfrac{17}{23} \)
Vậy \(\dfrac{13}{27} < \dfrac{17}{23}.\)
