The National Mathematics Advisory Panel specifies that children should be able to fluently add and subtract whole numbers by the end of third grade. Mathematical understanding of addition and subtraction emerges well before formal mathematic instruction begins, and when it emerges it reflects competence in a number of prerequisite skills and…

This study modeled school and district effects in the mathematics scores of the Delaware Student Testing Program (DSTP) using hierarchical linear modeling. Three-level hierarchical models were fitted to estimate school and district effects in the DSTP mathematics scores and to examine the school and district variance with variables assessing…