$\frac{2}{3}$ +$\frac{2}{15}$ +$\frac{2}{35}$ +$\frac{2}{63}$
=$\frac{2}{1.3}$+ $\frac{2}{3.5}$+ $\frac{2}{5.7}$ +$\frac{2}{7.9}$
=1-$\frac{1}{3}$+ $\frac{1}{3}$ -$\frac{1}{5}$+ $\frac{1}{5}$ -$\frac{1}{7}$ +$\frac{1}{7}$- $\frac{1}{9}$
=1+(-$\frac{1}{3}$+ $\frac{1}{3}$)+( -$\frac{1}{5}$+ $\frac{1}{5}$ )+(-$\frac{1}{7}$ +$\frac{1}{7}$)- $\frac{1}{9}$
=1-$\frac{1}{9}$
=$\frac{8}{9}$