3. Вычислите 6 a) 8.3== 7 1 5 6) 2.312= 12 7 в) 515 112 4 1 г) 72=2=

a) $$8 \cdot 3\frac{6}{7} = 8 \cdot \frac{27}{7} = \frac{216}{7} = 30\frac{6}{7}$$

б) $$2\frac{1}{8} \cdot 3\frac{5}{12} = \frac{17}{8} \cdot \frac{41}{12} = \frac{697}{96} = 7\frac{25}{96}$$

в) $$5\frac{12}{15} \cdot 1\frac{7}{12} = 5\frac{4}{5} \cdot 1\frac{7}{12} = \frac{29}{5} \cdot \frac{19}{12} = \frac{551}{60} = 9\frac{11}{60}$$

г) $$7\frac{4}{8} \cdot 2\frac{1}{6} = 7\frac{1}{2} \cdot 2\frac{1}{6} = \frac{15}{2} \cdot \frac{13}{6} = \frac{195}{12} = \frac{65}{4} = 16\frac{1}{4}$$

Ответ: a) $$30\frac{6}{7}$$; б) $$7\frac{25}{96}$$; в) $$9\frac{11}{60}$$; г) $$16\frac{1}{4}$$