5 4 + 2 3 {\displaystyle \ {\frac {5}{4}}+{\frac {2}{3}}\ } = {\displaystyle =} = 5 ⋅ 3 + 2 ⋅ 4 3 ⋅ 4 = 15 + 8 12 = 23 12 {\displaystyle ={\frac {5\cdot 3+2\cdot 4}{3\cdot 4}}={\frac {15+8}{12}}={\frac {23}{12}}}
