Tính

a)$\frac{2}{5}+\frac{3}{5}$  = ...........................................................................................................................

$\frac{1}{3}-\frac{2}{12}$ = ................................................................................................................................

$5+\frac{1}{4}$ = ..................................................................................................................................

$1-\frac{1}{2}+\frac{1}{6}$ = ...........................................................................................................................

b) $\frac{2}{7}+\frac{1}{5}$ = ...........................................................................................................................

$\frac{2}{3}-\frac{5}{8}$ = ................................................................................................................................

$\frac{7}{8}+\frac{1}{6}$ = ................................................................................................................................