  We describe how to evaluate approximately various physical interesting
quantities in random Ising systems by direct renormalization of a finite
system. The renormalization procedure is used to reduce the number of degrees
of freedom to a number that is small enough, enabling direct summing over the
surviving spins. This procedure can be used to obtain averages of functions of
the surviving spins. We show how to evaluate averages that involve spins that
do not survive the renormalization procedure. We show, for the random field
Ising model, how to obtain the "connected" 2-spin correlation function and the
"disconnected" 2-spin correlation function. Consequently, we show how to obtain
the average susceptibility and the average energy. For an Ising system with
random bonds and random fields we show how to obtain the average specific heat.
We conclude by presenting our numerical results for the average susceptibility
and the "connected" 2-spin correlation function along one of the principal
axes. (We believe this to be the first time, where the full three dimensional
correlation is calculated and not just parameters like Nu or Eta.) The results
for the average susceptibility are used to extract the critical temperature and
critical exponents of the 3D random field Ising system.
