*是乘以的意思 /是分数线
1/4*(4.85除以5/18-3.6+6.15*18/5)
=1/4*(4.85*18/5-18/5+6.15*18/5)
=1/4*18/5(4.85+6.15-1)
=1/4*18/5*10
=9