  Grassmann variables are used to formally transform a system with constraints
into an unconstrained system. As a result, the Schr\"{o}dinger equation arises
instead of the Wheeler-DeWitt one. The Schr\"{o}dinger equation describes a
system's evolution, but a definition of the scalar product is needed to
calculate the mean values of the operators. We suggest an explicit formula for
the scalar product related to the Klein-Gordon scalar product. The calculation
of the mean values is compared with an etalon method in which a redundant
degree of freedom is excluded. Nevertheless, we note that a complete
correspondence with the etalon picture is not found. Apparently, the picture
with Grassmann variables requires a further understanding of the underlying
Hilbert space.
