求
(a) $\frac{1}{2}$ of (i) $2\frac{3}{4}$ (ii) $4\frac{2}{9}$
(b) $\frac{5}{8}$ of (i) $3\frac{5}{6}$ (ii) $9\frac{2}{3}$
要求:
我们需要求
(a) (i) $2\frac{3}{4}$ (ii) $4\frac{2}{9}$
(b) (i) $3\frac{5}{6}$ (ii) $9\frac{2}{3}$
解答
(a)
(i) $2\frac{3}{4}$ 的 $\frac{1}{2}$
$2\frac{3}{4}=\frac{2\times4+3}{4}$
$=\frac{8+3}{4}$
$=\frac{11}{4}$
$2\frac{3}{4}$ 的 $\frac{1}{2}=\frac{11}{4}$ 的 $\frac{1}{2}$
$=\frac{1}{2}\times\frac{11}{4}$
$=\frac{1\times11}{2\times4}$
$=\frac{11}{8}$
(ii) $4 \frac{2}{9}$ 的 $\frac{1}{2}$
$4\frac{2}{9}=\frac{4\times9+2}{9}$
$=\frac{36+2}{9}$
$=\frac{38}{9}$
$4 \frac{2}{9}$ 的 $\frac{1}{2}=\frac{38}{9}$ 的 $\frac{1}{2}$
$=\frac{1\times38}{2\times9}$
$=\frac{38}{18}$
$=\frac{19}{9}$
(b)
(i) $3\frac{5}{6}$ 的 $\frac{5}{8}$
$3\frac{5}{6}=\frac{3\times6+5}{6}$
$=\frac{18+5}{6}$
$=\frac{23}{6}$
$3\frac{5}{6}$ 的 $\frac{5}{8}=\frac{5}{8}\times(\frac{23}{6})$
$=\frac{5\times23}{8\times6}$
$=\frac{115}{48}$
(ii) $9\frac{2}{3}$ 的 $\frac{5}{8}$
$9\frac{2}{3}=\frac{9\times3+2}{3}$
$=\frac{27+2}{3}$
$=\frac{29}{3}$
$9\frac{2}{3}$ 的 $\frac{5}{8}=\frac{5}{8}\times\frac{29}{3}$
$=\frac{5\times29}{8\times3}$
$=\frac{145}{24}$
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