a. $\frac{7}{9}+\frac{9}{10}=\frac{70 + 81}{10}=\frac{151}{10}$
b. $\frac{5}{6}+\frac{7}{8}=\frac{20 + 21}{24}=\frac{41}{24}$
c. $\frac{3}{5}+\frac{1}{2}+\frac{3}{10}=\frac{6+5+3}{10}=\frac{14}{10}=\frac{7}{5}$
a. $\frac{7}{9}+\frac{9}{10}=\frac{70 + 81}{10}=\frac{151}{10}$
b. $\frac{5}{6}+\frac{7}{8}=\frac{20 + 21}{24}=\frac{41}{24}$
c. $\frac{3}{5}+\frac{1}{2}+\frac{3}{10}=\frac{6+5+3}{10}=\frac{14}{10}=\frac{7}{5}$