  The well known Nakano-Nishijima-Gell-Mann (NNG) formula relates certain
quantum numbers of elementary particles to their charge number. This equation,
which phenomenologically introduces the quantum numbers $I_z$ (isospin), $S$
(strangeness), etc., is constructed using group theory with real numbers
$\mathbb{R}$. But, using a discrete Galois field $\mathbb{F}_p$ instead of
$\mathbb{R}$ and assuring the fundamental invariance laws such as unitarity,
Lorentz invariance, and gauge invariance, we derive the NNG formula deductively
from Meson (two quarks) and Baryon (three quarks) representations in a unified
way. Moreover, we show that quark confinement ascribes to the inevitable
fractionality caused by coprimeness between half-integer (1/2) of isospin and
number of composite particles (e.g. three).
