b4Math: Development and validation of a digital assessment for early numeracy in kindergarten classrooms

Early numeracy is a key foundation for later mathematical learning, yet validated assessment tools for preschool-aged children remain scarce in Latin American contexts. This study reports the development and psychometric validation of b4Math, a digital assessment designed to evaluate early numeracy in children attending the final year of preschool (age 5). The instrument assesses five domain-specific processes—cardinality, counting sequence, number identification, symbolic number comparison, and ordinality—aligned with early mathematics curricula. Data were collected from two Chilean cohorts (N = 357). Construct validity was examined using confirmatory factor analysis. Results supported a multidimensional structure with satisfactory reliability, measurement invariance across gender, and temporal stability. The multidimensional structure enables differentiated interpretation of early numeracy competencies. This structure supports domain-specific score interpretation for educational assessment and instructional planning in early childhood classrooms. Findings support b4Math as a practical digital tool for classroom-based assessment and monitoring.