  We show that the ABJM theory, which is an N=6 superconformal U(N)*U(N)
Chern-Simons gauge theory, can be studied for arbitrary N at arbitrary coupling
constant by applying a simple Monte Carlo method to the matrix model that can
be derived from the theory by using the localization technique. This opens up
the possibility of probing the quantum aspects of M-theory and testing the
AdS_4/CFT_3 duality at the quantum level. Here we calculate the free energy,
and confirm the N^{3/2} scaling in the M-theory limit predicted from the
gravity side. We also find that our results nicely interpolate the analytical
formulae proposed previously in the M-theory and type IIA regimes. Furthermore,
we show that some results obtained by the Fermi gas approach can be clearly
understood from the constant map contribution obtained by the genus expansion.
The method can be easily generalized to the calculations of BPS operators and
to other theories that reduce to matrix models.
