修一条公路，前4天修了1200米，照这样的速度，再修16天就可以修完，这条路共长多少米？（用比例解）
口算×15=×2=×=×=×= 1×=×=×34=×=×=×=×=×=×=×=×24=×=×30= 28×=×=
直接写出得数×15=×2=×=×= 1×=×=×34=×=×=×=×=×=
计算． 1×4.8 2×3.5 2.3×1 2×0.63．
口算：×15=×2=×=×=×= 1×=×=×34=×=×=×=×=
直接写出得数．×40=﹣=×= 2×= 24×=×22= 18×=×=×=×=
×15=
×2=
×
=
×
=
×
=
=
×
=
×34=
×
=
×
=
×
=
×
=
×
=
×
=
×
=
×24=
×
=
×30= 28×
=
×
=
×15=
×2=
×
=
×
=
=
×
=
×34=
×
=
×
=
×
=
×
=
×
=
×4.8 2
×3.5 2.3×1
2
×0.63．
×15=
×2=
×
=
×
=
×
= 1×
=
×
=
×34=
×
=
×
=
×
=
×
=
×40=
﹣
=
×
= 2×
= 24×
=
×22= 18×
=
×
=
×
=
×
=
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