5 4 : 3 7 {\displaystyle \ {\frac {5}{4}}:{\frac {3}{7}}\ } = 5 4 ⋅ 7 3 = 5 ⋅ 7 4 ⋅ 3 = 35 12 {\displaystyle \ ={\frac {5}{4}}\cdot {\frac {7}{3}}={\frac {5\cdot 7}{4\cdot 3}}={\frac {35}{12}}\qquad } ( 7 3 {\displaystyle \textstyle {\frac {7}{3}}} ist der Kehrwert von 3 7 {\displaystyle \textstyle {\frac {3}{7}}} )