3. Выполните действия: 1) 0,48 * 5/6; 2) 2 2/3 * 2,7; 3) 2,849 : 7/9; 4) 6,4 : 1 1/7

Решение:

• 1) \( 0,48 \times \frac{5}{6} = \frac{48}{100} \times \frac{5}{6} = \frac{48 \times 5}{100 \times 6} = \frac{240}{600} = \frac{2}{5} = 0.4 \)
• 2) \( 2\frac{2}{3} \times 2,7 = \frac{8}{3} \times \frac{27}{10} = \frac{8 \times 27}{3 \times 10} = \frac{216}{30} = \frac{36}{5} = 7.2 \)
• 3) \( 2,849 : \frac{7}{9} = \frac{2849}{1000} \times \frac{9}{7} = \frac{2849 \times 9}{1000 \times 7} = \frac{25641}{7000} \approx 3.663 \)
• 4) \( 6,4 : 1\frac{1}{7} = \frac{64}{10} : \frac{8}{7} = \frac{32}{5} \times \frac{7}{8} = \frac{32 \times 7}{5 \times 8} = \frac{224}{40} = \frac{28}{5} = 5.6 \)