Abstract
In a yoked control design, multicultural Head Start 4-year-olds played numerous games involving either numeracy or the oddity principle and insertions into series. Children showed better mastery of oddity and insertions after playing games directed at those two concepts. Numeracy scores on the McCarthy Scales of Children's Abilities (D. McCarthy, 1972) were equivalent for children who played numeracy games and children who played oddity and insertion games. These results are consistent with other research indicating that the understanding of oddity relations and that of insertions are key transitional thinking abilities that support numeracy at the preschool--kindergarten interface.