\(a\dfrac{2}{3}\times\dfrac{5}{7}=\dfrac{10}{21};\dfrac{10}{21}:\dfrac{5}{7}=\dfrac{10}{21}\times\dfrac{7}{5}=\dfrac{2}{3};\dfrac{10}{21}:\dfrac{2}{3}=\dfrac{10}{21}\times\dfrac{3}{2}=\dfrac{5}{7}\\ b.\dfrac{1}{5}\times\dfrac{1}{3}=\dfrac{1}{15};\dfrac{1}{15}:\dfrac{1}{5}=\dfrac{1}{3};\dfrac{1}{15}:\dfrac{1}{3}=\dfrac{1}{5}\)
a: 2/3x5/7=10/21
10/21:5/7=2/3
10/21:2/3=5/7
b: 1/5x1/3=1/15
1/15:1/5=1/3
1/15:1/3=1/5
a, \(\dfrac{2}{3}x\dfrac{5}{7}=\dfrac{2x5}{3x7}=\dfrac{10}{21}\\ \dfrac{10}{21}:\dfrac{5}{7}=\dfrac{10}{21}x\dfrac{7}{5}=\dfrac{10x7}{21x5}=\dfrac{2}{3}\\ \dfrac{10}{21}:\dfrac{2}{3}=\dfrac{10}{21}x\dfrac{3}{2}=\dfrac{10x3}{21x2}=\dfrac{5}{7}\)
b,
\(\dfrac{1}{5}x\dfrac{1}{3}=\dfrac{1x1}{5x3}=\dfrac{1}{15}\\ \dfrac{1}{15}:\dfrac{1}{5}=\dfrac{1}{15}x\dfrac{5}{1}=\dfrac{1x5}{15x1}=\dfrac{1}{3}\\ \dfrac{1}{15}:\dfrac{1}{3}=\dfrac{1}{15}x\dfrac{3}{1}=\dfrac{1x3}{15x1}=\dfrac{1}{5}\)
