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1 单位换算。(每空1分,共12分)
$3.9dm= ()cm$ $508m= ()cm$ $40cm= ()m$
$7.03dm= ()m$ $3400cm^{2}= ()m^{2}$ $2000dm^{2}= ()m^{2}$
$340cm^{2}= ()m^{2}$ $7.8m^{2}= ()cm^{2}$ $0.25dm^{3}= ()cm^{3}$
$2.5cm^{3}= ()dm^{3}$ $5000m^{3}= ()dm^{3}$ $560dm^{3}= ()m^{3}$
$3.9dm= ()cm$ $508m= ()cm$ $40cm= ()m$
$7.03dm= ()m$ $3400cm^{2}= ()m^{2}$ $2000dm^{2}= ()m^{2}$
$340cm^{2}= ()m^{2}$ $7.8m^{2}= ()cm^{2}$ $0.25dm^{3}= ()cm^{3}$
$2.5cm^{3}= ()dm^{3}$ $5000m^{3}= ()dm^{3}$ $560dm^{3}= ()m^{3}$
答案
39 50800 0.4
0.703 0.34 20
0.034 78000 250
0.0025 5000000 0.56
0.703 0.34 20
0.034 78000 250
0.0025 5000000 0.56
2 直接写出得数。(每题1分,共8分)
$6.9+4.5= $ $23×0.4= $ $0.6×1.5= $ $9.72-4.82= $
$80×0.3= $ $2.1-1.9= $ $0.225+0.775= $ $33÷10= $
$6.9+4.5= $ $23×0.4= $ $0.6×1.5= $ $9.72-4.82= $
$80×0.3= $ $2.1-1.9= $ $0.225+0.775= $ $33÷10= $
答案
11.4 9.2 0.9 4.9
24 0.2 1 3.3
24 0.2 1 3.3
3 计算下列各题,能简算的要简算。(每题3分,共18分)
$12.5×0.7×0.8$ $35÷(0.35×2)$ $4.6×0.35+4.6×0.65$
$7.28+0.94+2.72+0.06$ $5.83×2+4.27$ $73.5+26.5÷2.5$
$12.5×0.7×0.8$ $35÷(0.35×2)$ $4.6×0.35+4.6×0.65$
$7.28+0.94+2.72+0.06$ $5.83×2+4.27$ $73.5+26.5÷2.5$
答案
7 50 4.6
11 15.93 84.1
11 15.93 84.1
4 解方程。(每题4分,共12分)
$6.9x-2.4x= 13.5$ $7(x-1.2)= 4.2$ $5.67-x= 0.89$
$6.9x-2.4x= 13.5$ $7(x-1.2)= 4.2$ $5.67-x= 0.89$
答案
解:$x=3$ 解:$x=1.8$ 解:$x=4.78$
