你好!请笑纳哈。。。小括号里5/6,再除以5/6则中括号等于1,再1的多少次方都为1,则结果是等于19
20-[(1/2+1/3)除以5/6]*1.2=20-1×1.2=18.8
20-[(1/2+1/3)除以5/6]*1.2=20-[(5/6除以5/6]*1.2=20-1.2=18.8
20-[(1/2+1/3)÷5/6]×1.2=20-[(5/6)÷5/6]×1.2=20-1.2=18.8