Multiplicação e Divisão de Racionais

1. $0{,}5 \times 4 = 2$.

2. $2 \div 0{,}5 = 4$.

3. $\frac{1}{2} \times 8 = 4$.

4. $6 \div \frac{1}{3} = 6 \times 3 = 18$.

5. $\frac{2}{3} \times 9 = \frac{18}{3} = 6$.

6. $\frac{3}{4} \div 2 = \frac{3}{4} \times \frac{1}{2} = \frac{3}{8}$.

7. $1{,}5 \times \frac{2}{5} = \frac{3}{2} \times \frac{2}{5} = \frac{6}{10} = 0{,}6$.

8. $0{,}6 \div 3 = 0{,}2$.

9. $\frac{1}{3} \times x = 12 \Rightarrow x = 12 \times 3 = 36$.

10. $\frac{3}{4} \times x = 15 \Rightarrow x = 15 \times \frac{4}{3} = 20$.

11. $\frac{2}{3} \div \frac{1}{6} = \frac{2}{3} \times \frac{6}{1} = \frac{12}{3} = 4$.

12. $0{,}25 \times \frac{3}{2} = \frac{1}{4} \times \frac{3}{2} = \frac{3}{8} = 0{,}375$.

13. $\frac{3}{4} \div 3 = \frac{3}{4} \times \frac{1}{3} = \frac{3}{12} = \frac{1}{4}$ litro por pessoa.

14. $x \div \frac{2}{5} = 10 \Rightarrow x = 10 \times \frac{2}{5} = 4$.

15. $\frac{3}{5} \times \frac{2}{3} = \frac{6}{15} = \frac{2}{5}$. Depois $\frac{2}{5} \div \frac{1}{2} = \frac{2}{5} \times 2 = \frac{4}{5}$.

16. $0{,}8 \times \frac{1}{4} = 0{,}2$. Depois $0{,}2 \div 0{,}2 = 1$.