1. A device for teaching mathematical properties associated with even and odd numbers, comprising: an elongated channel having a plurality of longitudinal sides and end walls at each end, said elongated channel having markings placed thereon at equally spaced intervals; and a plurality of rods, each rod sized to fit at least partially within said channel, said plurality of rods being divided into two sets and including rods of different lengths, a first set having rods of only even lengths as defined with relation to said markings and a second set having rods of only odd lengths as defined with relation to said markings.