1. Вычислите: a) 2/3 ⋅ 1 2/7; б) 3 1/8 ⋅ 2; в) 1 1/7 ⋅ 1 3/4; г) 5/6 : 2 2/9; д) 3 3/5 : 9; e) 7 3/5 : 1 9/10. 2. Вычислите: a) 2 1/2 ⋅ 1 1/5 − 2 2/15 : 2; б) 4 3/7 ⋅ 8 4/9 − 4 3/7 ⋅ 6 4/9.

а) \[ \frac{2}{3} \cdot 1 \frac{2}{7} = \frac{2}{3} \cdot \frac{9}{7} = \frac{2 \cdot 9}{3 \cdot 7} = \frac{2 \cdot 3}{1 \cdot 7} = \frac{6}{7} \]

б) \[ 3 \frac{1}{8} \cdot 2 = \frac{25}{8} \cdot 2 = \frac{25 \cdot 2}{8} = \frac{25}{4} = 6 \frac{1}{4} \]

в) \[ 1 \frac{1}{7} \cdot 1 \frac{3}{4} = \frac{8}{7} \cdot \frac{7}{4} = \frac{8 \cdot 7}{7 \cdot 4} = \frac{8}{4} = 2 \]

г) \[ \frac{5}{6} : 2 \frac{2}{9} = \frac{5}{6} : \frac{20}{9} = \frac{5}{6} \cdot \frac{9}{20} = \frac{5 \cdot 9}{6 \cdot 20} = \frac{1 \cdot 3}{2 \cdot 4} = \frac{3}{8} \]

д) \[ 3 \frac{3}{5} : 9 = \frac{18}{5} : 9 = \frac{18}{5} \cdot \frac{1}{9} = \frac{18 \cdot 1}{5 \cdot 9} = \frac{2 \cdot 1}{5 \cdot 1} = \frac{2}{5} \]

е) \[ 7 \frac{3}{5} : 1 \frac{9}{10} = \frac{38}{5} : \frac{19}{10} = \frac{38}{5} \cdot \frac{10}{19} = \frac{38 \cdot 10}{5 \cdot 19} = \frac{2 \cdot 2}{1 \cdot 1} = 4 \]

а) \[ 2 \frac{1}{2} \cdot 1 \frac{1}{5} - 2 \frac{2}{15} : 2 = \frac{5}{2} \cdot \frac{6}{5} - \frac{32}{15} : 2 = \frac{5 \cdot 6}{2 \cdot 5} - \frac{32}{15} \cdot \frac{1}{2} = \frac{3}{1} - \frac{16}{15} = \frac{45}{15} - \frac{16}{15} = \frac{29}{15} = 1 \frac{14}{15} \]

б) \[ 4 \frac{3}{7} \cdot 8 \frac{4}{9} - 4 \frac{3}{7} \cdot 6 \frac{4}{9} = 4 \frac{3}{7} \cdot \left( 8 \frac{4}{9} - 6 \frac{4}{9} \right) = 4 \frac{3}{7} \cdot \left( 8 - 6 + \frac{4}{9} - \frac{4}{9} \right) = 4 \frac{3}{7} \cdot 2 = \frac{31}{7} \cdot 2 = \frac{62}{7} = 8 \frac{6}{7} \]