numitorul comun este 12
[tex] {}^{6)} \frac{3}{2} + {}^{4)} \frac{4}{3} + {}^{3)} \frac{5}{4} + {}^{2)} \frac{6}{6} = \\ \\ = \frac{18}{12} + \frac{16}{12} + \frac{15}{12} + \frac{12}{12} = \\ \\ = \frac{18 + 16 + 15 + 12}{12} = \\ \\ = \frac{61}{12} [/tex]
