We need to find the numbers corresponding to NSTIRK
Since K=5 & T=7
NILE NILE E+5=7, so E = 2 NIL2 E=2=I+I, so I=1 N1L2
+ RINK ---> + RIN5 -----> + RIN5 ----> + R1N5
TEST 7ES7 72S7 72S7
Now, we know I=1, E=2, K=5, & T=7, so other letters (N, R, L, & S) cannot = 1, 2, 5, or 7
N1L2 N+R=7, N & R= 3 or 4(assume N=3, R=4) 31L2
+R1N5 ---> +4135
72S7 72S7
L+3=S (L can't be 1,2,3,4,5. Also, it can't be more than 6, otherwise S=10 or above; so L=6)
3162
+ 4135 -----> NSTIRK = 397145 (the answer)
7297
I used this number to get to lvl50 (which is about where does the man live), and I have bookmarked the link~ But dunno why, the link is dead now.