Question

а)$frac{2}{3} + frac{1}{9} =$
б)$frac{3}{5} + frac{2}{7} =$
в)$frac{1}{6} + frac{3}{8} =$
г)$frac{2}{3} - frac{3}{5} =$
д)$frac{5}{6} - frac{1}{4} =$