The purpose of this study was to extend the research on the "Tests of Early Numeracy" (TEN) by following a cohort of 61 students from kindergarten through first grade. Specifically, this study examined the relationship between kindergarten and first-grade TEN measures built within and across school years and their predictive validity of a math curriculum-based measurement and teacher-derived measures of mathematics administered in first grade. Correlation analyses indicated significant relationships between kindergarten and first-grade TEN performance. Results from repeated-measures analyses of variance indicated that students made significant growth on all of the TEN measures from winter kindergarten to spring of first grade; however, different measures yielded significant growth within each grade. Kindergarten TEN performance also accounted for a significant amount of variance in first-grade computation skills and was moderately correlated with teacher ratings. (Contains 8 tables.)