Question

19．脫式計(jì)算．
3.6×2.5×0.4            
1.25×5.2×8         
4.9×0.8×0.32
0.6×1.35×5.3           
3.8×2.6×0.1        
50×0.24×8.7．

Answer 1

分析 ①運(yùn)用乘法結(jié)合律簡算；
②運(yùn)用乘法交換律簡算；
③④⑤⑥按照從左到右的順序計(jì)算，注意小數(shù)點(diǎn)的位置．

解答 解：①3.6×2.5×0.4 
=9×（2.5×0.4）
=9×1
=9；     
     
②1.25×5.2×8  
=1.25×8×5.2
=10×5.2
=52；      

③4.9×0.8×0.32
=3.92×0.32
=1.2544；

④0.6×1.35×5.3 
=0.81×5.3
=4.293；  
        
⑤3.8×2.6×0.1
=9.88×0.1
=0.988；       

⑥50×0.24×8.7
=12×8.7
=104.4．

點(diǎn)評 此題考查了小數(shù)的四則混合運(yùn)算，在計(jì)算時，注意運(yùn)算順序．