See me on one
after a second din
I'm the third man
I stopped solving at four
and I'm on five
Hint
B
The answer is the four-letter word:
ABEL
See me on one
An image of the US President, Abraham Lincoln - i.e. "Abe L" - appears on the US one-cent coin.
after a second din
Write 'ABEL' after the second letter of the English alphabet (B) to get B+ABEL=BABEL, a word meaning 'din' (a confused noise made by a number of voices).
I'm the third man
The third man according to Genesis was ABEL, the son of Adam and the younger brother of Cain.
I stopped solving at four
In mathematics, Abel's impossibility theorem (also known as the Abel-Ruffini theorem) states that there is 'no solution in radicals to general polynomial equations of degree five or higher with arbitrary coefficients'. In other words, it stops solving at [degree] four.
and I'm on five
An image of the US President, Abraham Lincoln - i.e. "Abe L" - appears on the US five-dollar bill, as well as on the penny!
As for the Hint:
This singular letter 'B' represents a Bel, the base unit of measurement for the intensity of sound (most usually expressed in 'decibels').
The title relates to...
...the three men referenced in this puzzle: Abraham Lincoln, Abel in the Bible, and the mathematician Niels Henrik Abel. They are 'quiet' because in sound intensity terms they are only 'a bel' - very quiet indeed!