Question

下面各题怎样算简便就怎样算．（1）3.2×2.5×1.25 （2）7.2...

下面各题怎样算简便就怎样算．（1）3.2×2.5×1.25 （2）7.26-5.4+1.74-1.6 （3）6.3÷45（4）2.8×0.5+0.5×28.2-0.5 （5）（1.62+1.62+1.62+1.62）÷1.8×2.5．

Answer 1

（1）3.2×2.5×1.25
=0.8×4×2.5×1.25
=（0.8×1.25）×（4×2.5）
=1×10
=10
        
（2）7.26-5.4+1.74-1.6 
=（7.26+1.74）-（5.4+1.6）
=9-7
=2
           
（3）6.3÷45
=6.3÷（9×5）
=6.3÷9÷5
=0.7÷5
=0.14

（4）2.8×0.5+0.5×28.2-0.5
=（2.8+28.2-1）×0.5
=30×0.5
=15
         
（5）（1.62+1.62+1.62+1.62）÷1.8×2.5
=（1.62×4）÷1.8×2.5
=1.62÷1.8×（2.5×4）
=0.9×10
=9