Children from low-income and ethnic minority backgrounds have demonstrated substantially lower levels of math achievement than their middle class majority peers for decades. The present study addressed two research questions: (1) when used as a supplement to typical classroom instruction and in isolation from the larger curriculum, does Building Blocks Software lead to improvements in math achievement as measured by proximal and distal measures of mathematics?; and (2) are the impacts of supplemental use of Building Blocks Software specific to math achievement? Nine Title 1 schools drawn from a large urban school district in Texas that primarily served students from low-income and ethnic minority backgrounds participated in this study. Forty kindergarten classrooms, all with full-day programming, participated. The sample consisted of 243 monolingual English speaking children (52% female). Most of these children represented ethnic minorities: 63% were African American, 30% Hispanic/Latino, 4% mixed ethnicity, 2% Caucasian, and 1% other. At the study's onset, the sample's scores on norm-referenced standardized tests of verbal ability (M = 84; SD = 14) and nonverbal ability (M = 77, SD = 11) were low average and below average, respectively, indicating risk for poor academic outcomes. Participants were randomized to receive computer assisted instruction with "Building Blocks Software" or "Earobics Step 1", a literacy software program. Randomized control trial; participants were randomized with equal probability from within classroom to one of the two experimental conditions. Children's numeracy skills were assessed with the "Research Based Early Math Assessment," a measure proximal to the Building Blocks Software at the beginning (i.e., pretest) and at the end (i.e., posttest) of children's kindergarten year. At posttest, the Applied Problems subtest from the "Woodcock-Johnson III Tests of Achievement," a distal measure of broad math achievement, was administered. To examine treatment specificity, vocabulary was assessed with the "Expressive One Word Picture Vocabulary Test" at pretest and posttest. Significant benefits for posttest math scores, but not vocabulary scores, were seen for children in the "Building Blocks Software" condition. For numeracy scores at posttest, there was a main effect for group, F(1, 178) = 8.08, p