(3.6*五分之七*4)+(0.35*1.8*二分之一)简便算法,

(3.6*五分之七*4)+(0.35*1.8*二分之一)
=36/10*7/5*4+35/100*18/10*1/2
=18/10*2*7/5*4+35/100*18/10*1/2
=18/10(56/5+7/40)
=9/5(7/5*8+7/5*1/8)
=9/5*7/5(8+1/8)
=9/5*7/5*65/8
=819/40
=20.475确定是对的？