a)
2 \frac{1}{5} * 10 + 1 \frac{3}{4}=\frac{11}{5}*10+1\frac{3}{4}=11*2+1\frac{3}{4}=22+1\frac{3}{4}=23\frac{3}{4}
\frac{2}{3} * \frac{4}{5} + 2 \frac{1}{2} =\frac{8}{15}+2\frac{1}{2}=\frac{16}{30}+2\frac{15}{30}=2\frac{31}{30}=3\frac{1}{30}
b)
3 \frac{3}{4} + 2 \frac{2}{3} * 2 \frac{1}{4} =3\frac{3}{4}+\frac{8}{3}*\frac{9}{4}=3\frac{3}{4}+\frac{24}{4}=3\frac{3}{4}+6=9\frac{3}{4}
[(1 \frac{1}{2})^2 + 1 \frac{1}{6}] * 3 =[(\frac{3}{2})^2+1\frac{1}{6}]*3=(\frac{9}{4}+\frac{7}{6})*3=\frac{27+14}{12}*3=\frac{41}{4}=10\frac{1}{4}
c)
2\frac{2}{5}*1\frac{2}{3}-1\frac{5}{6}=\frac{12}{5}*\frac{5}{3}-1\frac{5}{6}=4-1\frac{5}{6}=3\frac{6}{6}-1\frac{5}{6}=2\frac{1}{6}
4\frac{7}{8}-\frac{4}{3}*\frac{9}{8}=4\frac{7}{8}-\frac{12}{8}=4\frac{7}{8}-1\frac{4}{8}=3\frac{3}{8}