It is given that complex numbers  $Z_1$ and $Z_2$  satisfy  $\left|Z_1\right|=2$ and $\left|Z_2\right|$ =3. If the included angled of their corresponding vectors is ${60}^0$, then $\left|\frac{Z_1+Z_2}{Z_1-Z_2}\right|$  can be expressed as  $\frac{\sqrt{n}}{7}$, where ‘n’ is natural number then n =