Mẫu số chung: `30`
`2/3=(2xx10)/(3xx10)=20/30`
`1/2=(1xx15)/(2xx15)=15/30`
`4/5=(4xx6)/(5xx6)=24/30`
\(MSC:30\)
\(\dfrac{2}{3}=\dfrac{2\text{×}10}{3\text{×}10}=\dfrac{20}{30}\)
\(\dfrac{1}{2}=\dfrac{1\text{×}15}{2\text{×}15}=\dfrac{15}{30}\)
\(\dfrac{4}{5}=\dfrac{4\text{×}6}{5\text{×}6}=\dfrac{24}{30}\)
Vậy khi quy đồng các phân số\(\dfrac{2}{3};\dfrac{1}{2};\dfrac{4}{5}\) ta được các phân số\(\dfrac{20}{30};\dfrac{15}{30};\dfrac{24}{30}\)