a+2=3
a-2-2
a=1
Check
a+2=3
1+2=3
3=3
s+3=6
-3-3
s=3
Check
s+3=6
3+3=6
6=6
w-1=7
+1 +1
w=8
Check
w-1=7
8-1=7
7=7
d-8=1
+8 +8
d=9
Check
d-8=1
9-8=1
1=1
i-12=6
+12 +12
i=18
Check
i-12=6
18-12=6
6=6