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10.一个表面积是$60\ \mathrm{cm}^2$的长方体按如图所示的方式切三刀,分割成(
8
)个小长方体,这些小长方体的表面积之和比原来的长方体增加(60
)$\mathrm{cm}^2$。答案
10.8 60
三、计算题(共32分)
1.计算下面各题。(每题1分,共8分)
$\frac{7}{9}-\frac{4}{9}=$
$\frac{1}{3}+\frac{1}{4}=$
$2-\frac{9}{20}=$
$\frac{2}{3}+\frac{13}{5}-\frac{3}{5}=$
$0.625-\frac{3}{8}=$
$0.7+\frac{3}{10}=$
$(\quad)-\frac{2}{5}=1.4$
$3.3+\frac{1}{3}+2÷3=$
1.计算下面各题。(每题1分,共8分)
$\frac{7}{9}-\frac{4}{9}=$
$\frac{1}{3}+\frac{1}{4}=$
$2-\frac{9}{20}=$
$\frac{2}{3}+\frac{13}{5}-\frac{3}{5}=$
$0.625-\frac{3}{8}=$
$0.7+\frac{3}{10}=$
$(\quad)-\frac{2}{5}=1.4$
$3.3+\frac{1}{3}+2÷3=$
答案
1.$\frac{1}{3}$ $\frac{7}{12}$ $1\frac{11}{20}$ $2\frac{2}{3}$ $\frac{1}{4}$ 1 1.8 4.3
2.用合理的方法计算下面各题。(每题3分,共18分)
$1+(\dfrac{3}{20}+\dfrac{7}{20})$
$\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{7}{12}$
$\dfrac{30}{17}-(\dfrac{30}{17}-\dfrac{1}{9})$
$\dfrac{5}{4}-\dfrac{3}{8}+\dfrac{5}{8}$
$\dfrac{2}{5}+\dfrac{3}{4}-0.75$
$15-7÷15-\dfrac{8}{15}$
$1+(\dfrac{3}{20}+\dfrac{7}{20})$
$\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{7}{12}$
$\dfrac{30}{17}-(\dfrac{30}{17}-\dfrac{1}{9})$
$\dfrac{5}{4}-\dfrac{3}{8}+\dfrac{5}{8}$
$\dfrac{2}{5}+\dfrac{3}{4}-0.75$
$15-7÷15-\dfrac{8}{15}$
答案
2.$1\frac{1}{2}$ $\frac{1}{4}$ $\frac{1}{9}$ $1\frac{1}{2}$ $\frac{2}{5}$ 14
3.解方程。(每题2分,共6分)
$x-\frac{1}{8}=0.875$
$\frac{5}{6}-x=\frac{2}{3}$
$3x+0.1=0.7$
$x-\frac{1}{8}=0.875$
$\frac{5}{6}-x=\frac{2}{3}$
$3x+0.1=0.7$
答案
3.$x=1$ $x=\frac{1}{6}$ $x=0.2$
