Question

19．口算：

$\frac{2}{19}$×2=	$\frac{4}{15}×$8=	$\frac{7}{18}×$12=	$\frac{2}{7}×$2=	$\frac{3}{4}×$8=
$\frac{2}{3}×3$=	$\frac{2}{11}×2$=	$\frac{3}{14}×7$=	$\frac{2}{5}$×10=	$\frac{1}{6}$×2=
6×$\frac{2}{3}$=	5×$\frac{2}{7}$=	$\frac{7}{8}$×2=	$\frac{3}{4}$×3=	$\frac{3}{4}$×4=
$\frac{2}{9}$×7=	2×$\frac{2}{3}$=	$\frac{2}{5}$×2=	5×$\frac{2}{15}$=	57×$\frac{2}{19}$=
$\frac{2}{9}$×$\frac{3}{8}$=	$\frac{2}{9}×$0=	$\frac{25}{121}$×$\frac{11}{50}$=	$\frac{3}{4}$×$\frac{1}{2}$=	7×$\frac{3}{21}$=
$\frac{4}{5}$×$\frac{3}{8}$=	$\frac{7}{12}$×$\frac{3}{7}$=	$\frac{2}{5}$×10=	$\frac{9}{14}$×$\frac{35}{36}$=	5×$3\frac{2}{15}$=

Answer 1

分析 根據分數乘法的計算方法計算．

解答 解：

$\frac{2}{19}$×2=$\frac{4}{19}$	$\frac{4}{15}×$8=$\frac{32}{15}$	$\frac{7}{18}×$12=$\frac{14}{3}$	$\frac{2}{7}×$2=$\frac{4}{7}$	$\frac{3}{4}×$8=6
$\frac{2}{3}×3$=2	$\frac{2}{11}×2$=$\frac{4}{11}$	$\frac{3}{14}×7$=$\frac{3}{2}$	$\frac{2}{5}$×10=4	$\frac{1}{6}$×2=$\frac{1}{3}$
6×$\frac{2}{3}$=4	5×$\frac{2}{7}$=$\frac{10}{7}$	$\frac{7}{8}$×2=$\frac{7}{4}$	$\frac{3}{4}$×3=$\frac{9}{4}$	$\frac{3}{4}$×4=3
$\frac{2}{9}$×7=$\frac{14}{9}$	2×$\frac{2}{3}$=$\frac{4}{3}$	$\frac{2}{5}$×2=$\frac{4}{5}$	5×$\frac{2}{15}$=$\frac{2}{3}$	57×$\frac{2}{19}$=6
$\frac{2}{9}$×$\frac{3}{8}$=$\frac{1}{12}$	$\frac{2}{9}×$0=0	$\frac{25}{121}$×$\frac{11}{50}$=$\frac{1}{22}$	$\frac{3}{4}$×$\frac{1}{2}$=$\frac{3}{8}$	7×$\frac{3}{21}$=1
$\frac{4}{5}$×$\frac{3}{8}$=$\frac{3}{10}$	$\frac{7}{12}$×$\frac{3}{7}$=$\frac{1}{4}$	$\frac{2}{5}$×10=4	$\frac{9}{14}$×$\frac{35}{36}$=$\frac{5}{8}$	5×$3\frac{2}{15}$=15$\frac{2}{3}$

點評 本題考查了分數乘法的口算能力．是易錯題．