.
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ z \ + \ e \ + \ r \ + \ o \ = \ 0\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ o \ + \ n \ + \ e \ = \ 1\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ t \ + \ w \ + \ o \ = \ 2\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ t \ + \ h \ + \ r \ + \ e \ + \ e \ = \ 3\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ f \ + \ o \ + \ u \ + \ r \ = \ 4\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ f \ + \ i \ + \ v \ + \ e \ = \ 5\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ s \ + \ i \ + \ x \ = \ 6\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ s \ + \ e \ + \ v \ + \ e \ + \ n \ = \ 7\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ e \ + \ i \ + \ g \ + \ h \ + \ t \ = \ 8\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ n \ + \ i \ + \ n \ + \ e \ = \ 9\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ t \ + \ e \ + \ n \ = \ 10\)
\(\displaystyle e \ + \ l \ + \ e \ + \ v \ + \ e \ + \ n \ = \ 11\)
\(\displaystyle t \ + \ w \ + \ e \ + \ l \ + \ v \ + \ e \ = \ 12\)
when the variables are assigned as:
e = 3
f = 9
g = 6
h = 1
i = -4
l = 0
n = 5
o = -7
r = -6
s = -1
t = 2
u = 8
v = -3
w = 7
x = 11
z = 10
Source: Professor Stewart's Cabinet Of Mathematical Curiosities
by Ian Stewart
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ z \ + \ e \ + \ r \ + \ o \ = \ 0\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ o \ + \ n \ + \ e \ = \ 1\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ t \ + \ w \ + \ o \ = \ 2\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ t \ + \ h \ + \ r \ + \ e \ + \ e \ = \ 3\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ f \ + \ o \ + \ u \ + \ r \ = \ 4\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ f \ + \ i \ + \ v \ + \ e \ = \ 5\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ s \ + \ i \ + \ x \ = \ 6\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ s \ + \ e \ + \ v \ + \ e \ + \ n \ = \ 7\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ e \ + \ i \ + \ g \ + \ h \ + \ t \ = \ 8\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ n \ + \ i \ + \ n \ + \ e \ = \ 9\)
\(\displaystyle \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ t \ + \ e \ + \ n \ = \ 10\)
\(\displaystyle e \ + \ l \ + \ e \ + \ v \ + \ e \ + \ n \ = \ 11\)
\(\displaystyle t \ + \ w \ + \ e \ + \ l \ + \ v \ + \ e \ = \ 12\)
when the variables are assigned as:
e = 3
f = 9
g = 6
h = 1
i = -4
l = 0
n = 5
o = -7
r = -6
s = -1
t = 2
u = 8
v = -3
w = 7
x = 11
z = 10
Source: Professor Stewart's Cabinet Of Mathematical Curiosities
by Ian Stewart