Abstract

Early math skills are crucial for student learning and development. Sex gaps in math performance favoring male students have been well documented in different countries, with Chile being one of the countries with the highest sex gap in the world. However, it is still unclear at what point these differences manifest themselves. This work reports findings on differences between Chilean girls and boys aged 4 to 6 years in their math skills in the context of return to school after the COVID-19 lockdown. Multivariate analyses of variance in math learning data (N = 550) reveal similar skill levels between girls and boys at the initial evaluation—carried out right after two years of COVID-19 lockdown. However, after roughly three months of school attendance, we observed significant sex differences. Boys were favored in numerical comparison and perspective visualization tasks. Conversely, girls were favored in pattern creation and attribute seriation tasks. These findings are novel because they show sex differences in early childhood education and could guide the development of initiatives promoting equitable math teaching and learning. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.