Question

What is N – N?

Look at the following information:

O + T = T
O + S = S
T + T = F
F + F = E
E + O = N

What is N – N?

Answer 1

All the letters that provided in additional information refers first letter of numbers..

One + Two = Three
One + Six = Seven

Two + Two = Four

Four + Four = Eight

Eight + One = Nine

Similarly,

Nine – Nine = Zero i.e., N - N = Z

Answer 2

IF
O + T = T
O + S = S
T + T = F
F + F = E
E + O = N
THEN
N - N = Z