Question

4．口算．

$\frac{1}{6}$+$\frac{3}{4}$=	15×$\frac{2}{5}$=	$\frac{3}{5}$×$\frac{1}{2}$=	$\frac{2}{5}$×$\frac{3}{5}$=
$\frac{6}{19}$×0=	$\frac{8}{15}$×$\frac{3}{8}$=	$\frac{7}{11}$×7=	$\frac{3}{5}$-$\frac{3}{5}$=
17×$\frac{4}{51}$=	$\frac{10}{33}$×$\frac{22}{15}$=	$\frac{7}{16}$×$\frac{4}{21}$=	$\frac{9}{38}$×$\frac{9}{27}$=

Answer 1

分析 根据分数加减乘除法的计算方法进行计算．

解答 解：

$\frac{1}{6}$+$\frac{3}{4}$=$\frac{11}{12}$	15×$\frac{2}{5}$=6	$\frac{3}{5}$×$\frac{1}{2}$=$\frac{3}{10}$	$\frac{2}{5}$×$\frac{3}{5}$=$\frac{6}{25}$
$\frac{6}{19}$×0=0	$\frac{8}{15}$×$\frac{3}{8}$=$\frac{1}{5}$	$\frac{7}{11}$×7=$\frac{49}{11}$	$\frac{3}{5}$-$\frac{3}{5}$=0
17×$\frac{4}{51}$=$\frac{4}{3}$	$\frac{10}{33}$×$\frac{22}{15}$=$\frac{4}{9}$	$\frac{7}{16}$×$\frac{4}{21}$=$\frac{1}{12}$	$\frac{9}{38}$×$\frac{9}{27}$=$\frac{3}{38}$

点评 口算时，注意运算符号和数据，然后再进一步计算．