3/8 x 5 +4 1/6 x 2 1/10 - 9/20 x 6

$\frac{3}{8}\cdot5+4\frac{1}{6}\cdot2\frac{1}{10}-\frac{9}{20}\cdot6=7\frac{37}{40}=7,925$

1) $\frac{3}{8}\cdot5=\frac{3\cdot5}{8}=\frac{15}{8}=1\frac{7}{8}$

2) $4\frac{1}{6}\cdot2\frac{1}{10}=\frac{25}{6}\cdot\frac{21}{10}=\frac{25\cdot21}{6\cdot10}=\frac{5\cdot7}{2\cdot2}=\frac{35}{4}=8\frac{3}{4}$

3) $\frac{9}{20}\cdot6=\frac{9\cdot6}{20}=\frac{54}{20}=\frac{27}{10}=2\frac{7}{10}$

4) $1\frac{7}{8}+8\frac{3}{4}=\frac{15}{8}+\frac{35}{4}=\frac{15+70}{8}=\frac{85}{8}=10\frac{5}{8}$

5) $10\frac{5}{8}-2\frac{7}{10}=\frac{85}{8}-\frac{27}{10}=\frac{425-108}{40}=\frac{317}{40}=7\frac{37}{40}$