Упр.339 ГДЗ Мерзляк Полонский 6 класс (Математика)

1) 0,4* 5/9 ;
2) 8/27*0,75 ;
3) 1,5* 1/6 ;
4) 2*1/7*2,8.

1) $$0{,}4 \cdot \frac{5}{9} = \frac{4}{10} \cdot \frac{5}{9} = \frac{2}{5} \cdot \frac{5}{9} = \frac{2}{9}$$

2) $$\frac{8}{27} \cdot 0{,}75 = \frac{8}{27} \cdot \frac{75}{100} = \frac{8}{27} \cdot \frac{3}{4} = \frac{8 \cdot 3}{27 \cdot 4} = \frac{2}{9}$$

3) $$1{,}5 \cdot \frac{1}{6} = \frac{15}{10} \cdot \frac{1}{6} = \frac{3}{2} \cdot \frac{1}{6} = \frac{1}{2} \cdot \frac{1}{2} = \frac{1}{4}$$

4) $$2 \frac{1}{7} \cdot 2{,}8 = \frac{15}{7} \cdot \frac{28}{10} = \frac{15}{7} \cdot \frac{14}{5} = \frac{15 \cdot 14}{7 \cdot 5} = 6$$

Ответ

1) $$\frac{2}{9}$$; 2) $$\frac{2}{9}$$; 3) $$\frac{1}{4}$$; 4) $$6$$.