这分明是两个式子
(-7)+11+3+(-2)
= -7+11+3-2
=4+3-2
=7-2
=5
1/4+(-2/3)+5/6+(-1/4)+(-1/3)
=1/4-2/3+5/6-1/4-1/3
=（1/4-1/4）-（2/3+1/3）+（5/6）
=0-1+5/6
= -1+5/6
= -1/6