1 张大伯从家里的鱼塘里共捕捞出鲜鱼$1000\mathrm{kg}$,其中鲢鱼占$\frac{2}{7}$。如果将鲢鱼按每千克$6.3$元的价格卖给收购商,那么张大伯卖鲢鱼的收入是多少元?
答案:
$1000×\frac{2}{7}×6.3$
=1000×1.8
=1800(元)
答:张大伯的收入为1800元
=1000×1.8
=1800(元)
答:张大伯的收入为1800元
2 给下图的镜子安装一个镜框,镜框的周长是多少米?

答案:
$(\frac{7}{12}+\frac{5}{6})×2$
$ =\frac{17}{12}×2$
$ =\frac{17}{6}($米)
答:镜框的周长是$ \frac{17}{6}$米.
$ =\frac{17}{12}×2$
$ =\frac{17}{6}($米)
答:镜框的周长是$ \frac{17}{6}$米.
3 如下图所示,这个魔方的表面积和体积各是多少?

答案:
表面积$: \frac{2}{3}×\frac{2}{3}×6=\frac{8}{3}(dm²)$
体积$: \frac{2}{3}×\frac{2}{3}×\frac{2}{3}=\frac{8}{27}(dm³)$
答:表面积为$ \frac{8}{3}dm²,$体积为$ \frac{8}{27}dm³$
体积$: \frac{2}{3}×\frac{2}{3}×\frac{2}{3}=\frac{8}{27}(dm³)$
答:表面积为$ \frac{8}{3}dm²,$体积为$ \frac{8}{27}dm³$
1 直接写得数。
$4× \dfrac{2}{9}= $
$\dfrac{1}{6}× \dfrac{1}{3}= $
$\dfrac{4}{21}× 14= $
$4× \dfrac{2}{9}= $
$\frac{8}{9}$
$\dfrac{3}{7}× \dfrac{5}{6}= $$\frac{5}{14}$
$\dfrac{12}{13}× \dfrac{26}{15}= $$\frac{8}{5}$
$\dfrac{1}{6}× \dfrac{1}{3}= $
$\frac{1}{18}$
$\dfrac{9}{16}× 48= $27
$\dfrac{5}{4}× \dfrac{28}{35}= $1
$\dfrac{4}{21}× 14= $
$\frac{8}{3}$
$3× \dfrac{2}{7}= $$\frac{6}{7}$
$\dfrac{1}{24}× \dfrac{3}{10}= $$\frac{1}{80}$
答案:
$\frac{8}{9}$
$\frac{5}{14}$
$\frac{8}{5}$
$\frac{1}{18}$
27
1
$\frac{8}{3}$
$\frac{6}{7}$
$\frac{1}{80}$
$\frac{5}{14}$
$\frac{8}{5}$
$\frac{1}{18}$
27
1
$\frac{8}{3}$
$\frac{6}{7}$
$\frac{1}{80}$
2 下面各题,怎样简便就怎样算。
$\dfrac{4}{11}× \dfrac{4}{7}+\dfrac{4}{11}× \dfrac{3}{7}$ $1-\dfrac{3}{10}× \dfrac{4}{15}$ $\dfrac{11}{6}-\dfrac{9}{13}-\dfrac{4}{13}$
$\dfrac{2}{5}× 11-\dfrac{2}{5}$ $\dfrac{10}{19}× (\dfrac{2}{3}-\dfrac{1}{4})$ $\dfrac{5}{9}+\dfrac{4}{9}× 5$
$\dfrac{4}{11}× \dfrac{4}{7}+\dfrac{4}{11}× \dfrac{3}{7}$ $1-\dfrac{3}{10}× \dfrac{4}{15}$ $\dfrac{11}{6}-\dfrac{9}{13}-\dfrac{4}{13}$
$\dfrac{2}{5}× 11-\dfrac{2}{5}$ $\dfrac{10}{19}× (\dfrac{2}{3}-\dfrac{1}{4})$ $\dfrac{5}{9}+\dfrac{4}{9}× 5$
答案:
$ =\frac{4}{11}×(\frac{4}{7}+\frac{3}{7})$
$ =\frac{4}{11}×1$
$ =\frac{4}{11}$
$ =1-\frac{2}{25}$
$ =\frac{23}{25}$
$ =\frac{11}{6}-(\frac{9}{13}+\frac{4}{13})$
$ =\frac{11}{6}-1$
$ =\frac{5}{6}$
$ =\frac{2}{5}×(11-1)$
$ =\frac{2}{5}×10$
=4
$=\frac{10}{19}×\frac{5}{12}$
$ =\frac{25}{114}$
$=\frac{5}{9}+\frac{20}{9}$
$ =\frac{25}{9}$
$ =\frac{4}{11}×1$
$ =\frac{4}{11}$
$ =1-\frac{2}{25}$
$ =\frac{23}{25}$
$ =\frac{11}{6}-(\frac{9}{13}+\frac{4}{13})$
$ =\frac{11}{6}-1$
$ =\frac{5}{6}$
$ =\frac{2}{5}×(11-1)$
$ =\frac{2}{5}×10$
=4
$=\frac{10}{19}×\frac{5}{12}$
$ =\frac{25}{114}$
$=\frac{5}{9}+\frac{20}{9}$
$ =\frac{25}{9}$
3 $\dfrac{4}{25}km= $(
$\dfrac{6}{5}m^2= $(
1216
)m $\dfrac{3}{8}日= $(9
)时$\dfrac{6}{5}m^2= $(
120
)$dm^2$ $\dfrac{7}{4}kg= $(1750
)g
答案:
160
9
120
1750
9
120
1750
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