how do i work out $\displaystyle \frac {1}{2} + \frac {1}{3} + \frac {1}{4}$ , the answer is $\displaystyle \frac {13}{12}$ or $\displaystyle 1\frac {1}{12}$ but i can't seem to find the working out.

thanks

edit:dw i found the solution $\displaystyle \frac {6}{12} + \frac {4}{12} + \frac {3}{12}$