2\frac{1}{10} \cdot 4\frac{1}{6} + 5 \cdot \frac{3}{8} - \frac{9}{20} \cdot 6

Решим пример по действиям:

1. $$2\frac{1}{10} \cdot 4\frac{1}{6} = \frac{21}{10} \cdot \frac{25}{6} = \frac{21 \cdot 25}{10 \cdot 6} = \frac{7 \cdot 5}{2 \cdot 2} = \frac{35}{4} = 8\frac{3}{4}$$
2. $$5 \cdot \frac{3}{8} = \frac{5 \cdot 3}{8} = \frac{15}{8} = 1\frac{7}{8}$$
3. $$\frac{9}{20} \cdot 6 = \frac{9 \cdot 6}{20} = \frac{9 \cdot 3}{10} = \frac{27}{10} = 2\frac{7}{10}$$
4. $$8\frac{3}{4} + 1\frac{7}{8} = 8\frac{6}{8} + 1\frac{7}{8} = 9\frac{13}{8} = 10\frac{5}{8}$$
5. $$10\frac{5}{8} - 2\frac{7}{10} = 10\frac{25}{40} - 2\frac{28}{40} = 9\frac{65}{40} - 2\frac{28}{40} = 7\frac{37}{40}$$

Ответ: $$7\frac{37}{40}$$