5 б) в при b = 1, b= 5, b= 6, b= 84, b = 0. 12 5' 12' 5' 25'

а) $$ \frac{5}{12} \cdot \frac{1}{5} = \frac{5 \cdot 1}{12 \cdot 5} = \frac{1}{12} $$

б) $$ \frac{5}{12} \cdot \frac{5}{12} = \frac{5 \cdot 5}{12 \cdot 12} = \frac{25}{144} $$

в) $$ \frac{5}{12} \cdot \frac{6}{5} = \frac{5 \cdot 6}{12 \cdot 5} = \frac{6}{12} = \frac{1}{2} $$

г) $$ \frac{5}{12} \cdot \frac{84}{25} = \frac{5 \cdot 84}{12 \cdot 25} = \frac{5 \cdot 12 \cdot 7}{12 \cdot 5 \cdot 5} = \frac{7}{5} = 1 \frac{2}{5} $$

д) $$ \frac{5}{12} \cdot 0 = 0 $$

Ответ: а) $$\frac{1}{12}$$; б) $$\frac{25}{144}$$; в) $$\frac{1}{2}$$; г) $$1 \frac{2}{5}$$; д) 0