7-=0
13-=5
18-=7
-3=3
-6=6
-8=13
5+=10
3+=14
12+=30
16+7=
22+12=
34+7=
36-15=
23-16=
32-8=

-4=15-3
+8=17+4
++8=31
-12-=10
11+=-11
14+14+13+12=
8-=+8
66+39-38=