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一、口算。
$0.314×100=$
$3.14×0.3^{2}=$
$3.14×2^{2}=$
$3.14×90=$
$3.14×4^{2}=$
$3.14×0.2^{2}=$
$3.14×200^{2}=$
$0.314×100=$
31.4
$\frac {5}{9}×60\% =$$\dfrac{1}{3}$
$3.6×1000=$3600
$3.14×0.3^{2}=$
0.2826
$\frac {5}{6}÷\frac {11}{12}=$$\dfrac{10}{11}$
$4÷80\% =$5
$3.14×2^{2}=$
12.56
$46.8×100=$4680
$15\% +\frac {2}{5}=$$\dfrac{11}{20}$
$3.14×90=$
282.6
$\frac {7}{6}×\frac {3}{7}=$$\dfrac{1}{2}$
$20÷\frac {4}{5}=$25
$3.14×4^{2}=$
50.24
$2.75+3.25=$6
$\frac {7}{20}-\frac {1}{5}=$$\dfrac{3}{20}$
$3.14×0.2^{2}=$
0.1256
$0.39÷1.3=$0.3
$2-\frac {3}{7}=$$1\dfrac{4}{7}$
$3.14×200^{2}=$
125600
$3.65+0.4=$4.05
$\frac {1}{9}+\frac {1}{6}=$$\dfrac{5}{18}$
答案
一、31.4 $\dfrac{1}{3}$ 3600
0.2826 $\dfrac{10}{11}$ 5
12.56 4680 $\dfrac{11}{20}$
282.6 $\dfrac{1}{2}$ 25
50.24 6 $\dfrac{3}{20}$
0.1256 0.3 $1\dfrac{4}{7}$
125600 4.05 $\dfrac{5}{18}$
0.2826 $\dfrac{10}{11}$ 5
12.56 4680 $\dfrac{11}{20}$
282.6 $\dfrac{1}{2}$ 25
50.24 6 $\dfrac{3}{20}$
0.1256 0.3 $1\dfrac{4}{7}$
125600 4.05 $\dfrac{5}{18}$
二、计算圆柱的表面积。
答案
二、$2× 3.14× 4× 8+3.14× 4^{2}× 2=301.44(\mathrm{cm}^{2})$
$3.14× 6× 12+3.14× (6÷ 2)^{2}× 2=282.6(\mathrm{dm}^{2})$
$3.14× 6× 12+3.14× (6÷ 2)^{2}× 2=282.6(\mathrm{dm}^{2})$
