sábado, 15 de dezembro de 2012

Exercícios de multiplicação e divisão de fração

Resolva as seguintes frações e simplifique se necessário:


(a) $\frac{2}{3} \times 5 \div \frac{6}{8} = $

(b) $\frac{3}{2} \times \frac{2}{3} =$

(c) $\frac{2}{3}\times \frac{5}{3}=$

(d) $\frac{3}{4} \times \frac{5}{6} \times \frac{7}{8}=$

(e)$\frac{9}{8} \times 4 \times 2 =$

(f) $\frac{1}{2} \div \frac{5}{6}=$

(g)$\frac{2}{3}\div \frac{4}{5}=$

(h)$\frac{4}{5} \div \frac{7}{4} \div 6=$

(i)$ \frac{2}{9} \div 3\times \frac{7}{8}=$

(j)$\frac{7}{8} \times 9 \div 3=$

(k)$ 8 \div 7 \div 2=$


Respostas com resolução:



(a)$\frac{2}{3} \times 5 \div \frac{6}{8} = \frac{80}{18} =\frac{40}{9}$


(b)$\frac{3}{2} \times \frac{2}{3} =\frac{6}{6} = 1$


(c)$\frac{2}{3}\times \frac{5}{3}= \frac{10}{9}$


(d)$\frac{3}{4} \times \frac{5}{6} \times \frac{7}{8}=\frac{105}{192}$


(e)$\frac{9}{8} \times 4 \times 2 = 9$


(f) $\frac{1}{2} \div \frac{5}{6}= \frac{1}{2} \times \frac{6}{5} =\frac{6}{10}=\frac{3}{5}$



(g)$\frac{2}{3}\div \frac{4}{5}= \frac{2}{3}\times\frac{5}{4}=\frac{10}{12}=\frac{5}{6}$


(h)$\frac{4}{5} \div \frac{7}{4} \div 6=\frac{4}{5}\times\frac{4}{7}\times \frac{1}{6} =\frac{16}{210} = \frac{8}{105}$


(i)$ \frac{2}{9} \div 3\times \frac{7}{8}=\frac{2}{9}\times\frac{1}{3}\times\frac{7}{8} =\frac{14}{216}=\frac{7}{108}$


(j)$\frac{7}{8} \times 9 \div 3= \frac{7}{8} \times 9 \times \frac{1}{3} = \frac{63}{24}=\frac{21}{8}$


(k)$ 8 \div 7 \div 2= 8\times\frac{1}{7}\times\frac{1}{2}=\frac{8}{14}\frac{4}{7}$