  Simple transformation formulas between fermion matrices and observables, and
numerical values of quark matrices, are obtained on a particular weak basis
with one quark matrix diagonal and the other with vanishing elements 1-1, 1-3
and 3-1, and with only the element 2-2 complex. When we choose $M_u$ diagonal,
then $M_d$ shows intriguing numerical properties which suggest a four parameter
description of it, which implies $V_{us}\simeq \sqrt{m_d/m_s}$, $V_{cb}\simeq
(3/\sqrt{5})(m_s/m_b)$ and $V_{ub}\simeq (1/\sqrt{5})(\sqrt{m_d m_s}/m_b)$. Few
comments on mass-mixing relations are added.
