Giải:
a) \(\dfrac{14}{21}=\dfrac{2}{3}=\dfrac{2.2}{3.2}=\dfrac{4}{6}\)
\(\dfrac{60}{72}=\dfrac{5}{6}\)
Vì \(\dfrac{4}{6}< \dfrac{5}{6}\) nên \(\dfrac{14}{21}< \dfrac{60}{72}\)
b) \(\dfrac{11}{54}=\dfrac{11.2}{54.2}=\dfrac{22}{108}\)
\(\dfrac{22}{37}\)
Vì \(\dfrac{22}{108}< \dfrac{22}{37}\) nên \(\dfrac{11}{54}< \dfrac{22}{37}\)
c) \(\dfrac{-2}{15}\)
\(\dfrac{-24}{72}=\dfrac{-1}{3}=\dfrac{-1.5}{3.5}=\dfrac{-5}{15}\)
Vì \(\dfrac{-2}{15}>\dfrac{-5}{15}\) nên \(\dfrac{-2}{15}>\dfrac{-24}{72}\)
d) \(\dfrac{24}{49}=\dfrac{24.23}{49.23}=\dfrac{552}{1127}\)
\(\dfrac{23}{45}=\dfrac{23.24}{45.24}=\dfrac{552}{1080}\)
Vì \(\dfrac{552}{1127}< \dfrac{552}{1080}\) nên \(\dfrac{24}{49}< \dfrac{23}{45}\)
