(-30分之1)/(3分之1-5分之1-15分之1)
= (-1/30)/(5/15-3/15-1/15)
=(-1/30)/(5/15-3/15-1/15)
=(-1/30)/(1/15)
= -1/2解法二：原式= (-1/30)÷[(2/3+1/6)-(1/10+2/5)]= (-1/30)÷(5/6-1/2)= -1/30×3= -1/10你想问什么？原式是上面的题目的话就是错了。