Early math skills in kindergarten are strongly linked to later mathematics achievement. A longitudinal study followed children from kindergarten to third grade, finding that kindergarten number competence predicted mathematics performance and growth in later grades. Children with weaker number skills in kindergarten had slower progress in math, while those who started kindergarten later showed better math performance, which was explained by their stronger number skills. The study highlights the importance of early number competence in setting children's math learning trajectories. Number competence involves understanding numbers, counting, and basic operations, and is distinct from more complex math knowledge. Weak number skills are associated with math difficulties, including poor counting, slow fact retrieval, and inaccurate computation. Early number competence can be improved through targeted instruction and activities. The study also found that low-income children had lower math achievement and slower growth, which was mediated by weaker number skills in kindergarten. The findings suggest that early number competence is a critical factor in math development and should be prioritized in early education. The study used a sequential process growth curve model to analyze the relationship between number competence and math achievement, finding that kindergarten number competence predicted math performance and growth in later grades. The results emphasize the need for early intervention to support math development, particularly for children from low-income families.Early math skills in kindergarten are strongly linked to later mathematics achievement. A longitudinal study followed children from kindergarten to third grade, finding that kindergarten number competence predicted mathematics performance and growth in later grades. Children with weaker number skills in kindergarten had slower progress in math, while those who started kindergarten later showed better math performance, which was explained by their stronger number skills. The study highlights the importance of early number competence in setting children's math learning trajectories. Number competence involves understanding numbers, counting, and basic operations, and is distinct from more complex math knowledge. Weak number skills are associated with math difficulties, including poor counting, slow fact retrieval, and inaccurate computation. Early number competence can be improved through targeted instruction and activities. The study also found that low-income children had lower math achievement and slower growth, which was mediated by weaker number skills in kindergarten. The findings suggest that early number competence is a critical factor in math development and should be prioritized in early education. The study used a sequential process growth curve model to analyze the relationship between number competence and math achievement, finding that kindergarten number competence predicted math performance and growth in later grades. The results emphasize the need for early intervention to support math development, particularly for children from low-income families.