In this study, we examine whether preventive enrichment of pre-math skills has an influence on number knowledge in preschool children from low income families. Our data analyses use two methods to examine the influence of two independent programs implemented during junior kindergarten and kindergarten. The first implies the traditional approach comparing the self-selected treated group to a self-selected comparison group. The second approach uses a self-selected dosage approach to the treatment condition, considering that implementation of the program varied across teachers. The results regarding the enrichment program in kindergarten were inconclusive. Nevertheless, the pre-math program implemented in junior kindergarten showed a positive influence on children's core requisite skills for later learning of arithmetic. Although children were receptive during both preschool years, a junior kindergarten program that elaborates upon conceptual issues beyond the number line appears both feasible and beneficial over the short-term.