\(\Large \dfrac{6}{15}\) \(\Large \dfrac{20}{12}\) \(\Large \dfrac{15}

• A. \(\Large \dfrac{6}{15}\)
• B. \(\Large \dfrac{20}{12}\)
• C. \(\Large \dfrac{15}{25}\)
• D. \(\Large \dfrac{18}{36}\)

\(\Large \dfrac{6}{15} = \dfrac{6 : 3}{15 : 3} = \dfrac{2}{5}\) 

\(\Large \dfrac{20}{12} = \dfrac{20 : 4}{12 : 4} = \dfrac{5}{3}\) 

\(\Large \dfrac{15}{25} = \dfrac{15 : 5}{25 : 5} = \dfrac{3}{5}\) 

\(\Large \dfrac{18}{36} = \dfrac{18 : 18}{36 : 18} = \dfrac{1}{2}\) 

Vậy ta chọn phân số \(\Large \dfrac{15}{25}\).