Question

3．口算．

65×$\frac{2}{5}$=	$\frac{1}{2}$×$\frac{3}{4}$=	$\frac{2}{9}$×3=	$\frac{1}{2}$×$\frac{4}{5}$=
$\frac{2}{7}$+$\frac{1}{8}$=	$\frac{3}{5}$×$\frac{3}{4}$=	$\frac{9}{2}$×$\frac{1}{4}$=	$\frac{4}{7}$×$\frac{2}{3}$=

Answer 1

分析 根據(jù)分數(shù)乘法、分數(shù)加法的計算法則，依次進行計算即可．

解答 解：

65×$\frac{2}{5}$=26	$\frac{1}{2}$×$\frac{3}{4}$=$\frac{3}{8}$	$\frac{2}{9}$×3=$\frac{2}{3}$	$\frac{1}{2}$×$\frac{4}{5}$=$\frac{2}{5}$
$\frac{2}{7}$+$\frac{1}{8}$=$\frac{23}{56}$	$\frac{3}{5}$×$\frac{3}{4}$=$\frac{9}{20}$	$\frac{9}{2}$×$\frac{1}{4}$=$\frac{9}{8}$	$\frac{4}{7}$×$\frac{2}{3}$=$\frac{8}{21}$

點評 靈活掌握分數(shù)加法和分數(shù)乘法的計算法則，是解答此題的關(guān)鍵．