\(a,\dfrac{3}{8}=\dfrac{3.7}{8.7}=\dfrac{21}{56}\\ \dfrac{5}{7}=\dfrac{5.8}{7.8}=\dfrac{40}{56}\\ b,\dfrac{1}{5}=\dfrac{12}{60}\\ \dfrac{2}{3}=\dfrac{2.20}{60}=\dfrac{40}{60}\\ \dfrac{3}{4}=\dfrac{3.15}{60}=\dfrac{45}{60}\\ c,\dfrac{3}{16}=\dfrac{3.3}{48}=\dfrac{9}{48};\dfrac{5}{48};\\ \dfrac{3}{8}=\dfrac{3.6}{48}=\dfrac{18}{48}\)

4 và 5