We consider two model held theories on a noncommutative plane that have a s
mooth commutative limit. One is the nonrelativistic single-component fermio
n theory with a quartic interaction that vanishes identically in the commut
ative limit. The other is a scalar-fermion theory, which extends the scalar
field theory with a quartic interaction by adding a fermion. We show the s
mooth commutative limits by computing the bound state energies and the two
particle scattering amplitudes exactly.