简便计算.能简便的简便4/5X3.5+5.5X50%+0.8 6/7X（4/5-1/3）÷3/50.25X3.2X1.2

简便计算.能简便的简便
4/5X3.5+5.5X50%+0.8
解,得：
==0.8*3.5+5.5*0.5+0.8
==0.8*(3.5+1)+5.5*0.5
==0.8*4.5+5.5*(0.8-0.3)
==0.8*4.5+5.5*0.8-0.3*5.5
==(4.5+5.5)*0.8-0.3*5.5
==10*0.8-0.3*5.5
==8-1.65
==6.35
6/7X（4/5-1/3）÷3/5
解,得：
==(6/7)X（7/15）*(5/3)
==2/3
0.25X3.2X1.25
解,得：
==0.25X0.4*(8X1.25 )
==0.1*10
==1
0.5+5/6X（0.15+9/20)
解,得：
==0.5+5/6X（3/20+9/20)
==1/2+5/6X（3/5)
==1/2+1/2
==1