\(\displaystyle{{ - 8} \over {15}} = {{ - 32} \over {60}} = {{ - 15 + ( -12) + ( - 5)} \over {60}} \)
\(\displaystyle= {{ - 15} \over {60}} + {{ - 12} \over {60}} + {{ - 5} \over {60}}\)\(\displaystyle = {{ - 1} \over 4} + {{ - 1} \over 5} + {{ - 1} \over {12}}.\)