a) $\frac{1}{5}+\frac{1}{5}+\frac{1}{5}=3\cdot \frac{1}{5}=\frac{3\cdot 1}{5}=\frac{3}{5}$

b) $\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}=7\cdot \frac{3}{10}=\frac{7\cdot 3}{10}=\frac{21}{10}=2\frac{1}{10}$ $\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}+\frac{3}{10}=7\cdot \frac{3}{10}=\frac{7\cdot 3}{10}=\frac{21}{10}=2\frac{1}{10}$

c) $\frac{7}{8}+\frac{7}{8}+\frac{7}{8}+\frac{7}{8}=4\cdot \frac{7}{8}=\frac{4\cdot 7}{8}=\frac{1\cdot 7}{2}=\frac{7}{2}=3\frac{1}{2}$

d) $1\frac{3}{8}+1\frac{3}{8}=\frac{11}{8}+\frac{11}{8}=2\cdot \frac{11}{8}=\frac{2\cdot 11}{8}=\frac{1\cdot 11}{4}=\frac{11}{4}=2\frac{3}{4}$

e) $3\frac{2}{3}+3\frac{2}{3}+3\frac{2}{3}=\frac{11}{3}+\frac{11}{3}+\frac{11}{3}=3\cdot \frac{11}{3}=\frac{3\cdot 11}{3}=\frac{1\cdot 11}{1}=11$

f) $2\frac{1}{2}+2\frac{1}{2}+2\frac{1}{2}+2\frac{1}{2}+2\frac{1}{2}=\frac{5}{2}+\frac{5}{2}+\frac{5}{2}+\frac{5}{25}/2=5\cdot \frac{5}{2}=\frac{5\cdot 5}{2}=\frac{25}{2}=12\frac{1}{2}$