In brain teasers, TRN is a shorthand way of saying the Right Number.
TRN is often an abbreviation for “the answer is” or “the result is not” but most commonly it stands for: three right numbers or more specifically the right number.
However, in some cases, TRN can also stand for: three random numbers. By using TRN, brain teaser creators can add an extra layer of challenge and excitement to their puzzles.
