Thực hiện phép tính (tính hợp lí nếu có thể): l) − 3/13 + − 7/17 + − 5/19 + − 10/13 + 24/17 + − 14/19 .

l) \(\frac{{ - 3}}{{13}} + \frac{{ - 7}}{{17}} + \frac{{ - 5}}{{19}} + \frac{{ - 10}}{{13}} + \frac{{24}}{{17}} + \frac{{ - 14}}{{19}}\)

\[ = \left( {\frac{{ - 3}}{{13}} + \frac{{ - 10}}{{13}}} \right) + \left( {\frac{{ - 7}}{{17}} + \frac{{24}}{{17}}} \right) + \left( {\frac{{ - 5}}{{19}} + \frac{{ - 14}}{{19}}} \right)\]

\[ = \frac{{ - 13}}{{13}} + \frac{{17}}{{17}} + \frac{{ - 19}}{{19}}\]

\[ = \left( { - 1} \right) + 1 + \left( { - 1} \right)\]

\( = - 1.\)