Giúp em vs ạ e cần gấp

1)

$\frac{1}{3} + \frac{1}{4} = \frac{4}{12} + \frac{3}{12} = \frac{4+3}{12} = \frac{7}{12}$
2)

$\frac{2}{3} - \frac{3}{4} = \frac{8}{12} - \frac{9}{12} = \frac{8-9}{12} = -\frac{1}{12}$
3)

$\frac{3}{5} - \frac{2}{3} = \frac{9}{15} - \frac{10}{15} = \frac{9-10}{15} = -\frac{1}{15}$
4)

$-\frac{1}{5} + \frac{5}{2} = -\frac{2}{10} + \frac{25}{10} = \frac{-2+25}{10} = \frac{23}{10}$
5)

$\frac{1}{4} + \frac{-2}{5} = \frac{1}{4} - \frac{2}{5} = \frac{5}{20} - \frac{8}{20} = \frac{5-8}{20} = -\frac{3}{20}$
6)

$\frac{5}{6} - \frac{-7}{5} = \frac{5}{6} + \frac{7}{5} = \frac{25}{30} + \frac{42}{30} = \frac{25+42}{30} = \frac{67}{30}$