Помогите решить 1)1 2/3+2 1/4 2)3 1/3+4 2/5 3)3/5-1/5 4)4/7-6/7 5)5/7-3/5 6) 7/9-9/10

1)
$1 \frac{2}{3} + 2 \frac{1}{4} = 1 \frac{8}{12} + 2 \frac{3}{12} = 3 \frac{11}{12}$
2)
$3 \frac{1}{3} + 4 \frac{2}{5} = 3 \frac{5}{15} + 4 \frac{6}{15} = 7 \frac{11}{15}$
3)
$\frac{3}{5} - \frac{1}{5} = \frac{2}{5}$
4)
$\frac{4}{7} - \frac{6}{7} = - \frac{2}{7}$
5)
$\frac{5}{7} - \frac{3}{5} = \frac{25}{35} - \frac{21}{35} = \frac{4}{35}$
6)
$\frac{7}{9} - \frac{9}{10} = \frac{70}{90} - \frac{81}{90} = - \frac{11}{90}$