[tex] \frac{1}{60} : ( - \frac{1}{30}) - ( - \frac{6}{10}) = \frac{1}{60} : - \frac{1}{30} - ( - \frac{3}{5}) = \frac{1}{60} \times \frac{30}{ - 1} - ( - \frac{3}{5}) = \frac{1 \times 30}{ - 60} - ( - \frac{3}{5}) = \frac{30}{ - 60} - ( - \frac{3}{5}) = - \frac{30}{60} - ( - \frac{3}{5}) = - \frac{1}{2} - ( - \frac{3}{5}) = - \frac{1}{2} + \frac{3}{5} = \frac{1}{10} [/tex]
