计算
(i) $12\div\frac{3}{4}$
(ii) $14\div\frac{5}{6}$
(iii) $8\div\frac{7}{3}$
(iv) $4\div\frac{8}{3}$
(v) $3\div2\frac{1}{3}$
(vi) $5\div3\frac{4}{7}$
解题步骤
我们需要计算
(i) $12\div\frac{3}{4}$
(ii) $14\div\frac{5}{6}$
(iii) $8\div\frac{7}{3}$
(iv) $4\div\frac{8}{3}$
(v) $3\div2\frac{1}{3}$
(vi) $5\div3\frac{4}{7}$
解答
我们知道:
$\frac{a}{b} \div \frac{c}{d}=\frac{a}{b} \times \frac{d}{c}$
因此:
(i) $12\div\frac{3}{4}=12\times\frac{1}{\frac{3}{4}}$
$=12\times\frac{4}{3}$
$=\frac{12\times4}{3}$
$=\frac{48}{3}=16$
$=16$
(ii) $14\div\frac{5}{6}=14\times\frac{1}{\frac{5}{6}}$
$=14\times\frac{6}{5}$
$=\frac{14\times6}{5}$
$=\frac{84}{5}$
(iii) $8\div\frac{7}{3}=8\times\frac{1}{\frac{7}{3}}$
$=8\times\frac{3}{7}$
$=\frac{8\times3}{7}$
$=\frac{24}{7}$
(iv) $4\div\frac{8}{3}=4\times\frac{1}{\frac{8}{3}}$
$=4\times\frac{3}{8}$
$=\frac{4\times3}{8}$
$=\frac{3}{2}$
(v) $3\div2\frac{1}{3}=3\div\frac{2\times3+1}{3}$
$=3\div\frac{6+1}{3}$
$=3\div\frac{7}{3}$
$=3\times\frac{1}{\frac{7}{3}}$
$=3\times\frac{3}{7}$
$=\frac{3\times3}{7}$
$=\frac{9}{7}$
(vi) $5\div3\frac{4}{7}=5\div\frac{3\times7+4}{7}$
$=5\div\frac{21+4}{7}$
$=5\div\frac{25}{7}$
$=5\times\frac{1}{\frac{25}{7}}$
$=5\times\frac{7}{25}$
$=\frac{5\times7}{25}$
$=\frac{7}{5}$