LAUSR

Across the first years of schooling, children learn numerical information that is foundational to mathematical learning. Individual differences in math skills and the math learning support children receive at home may be related to their brain activity when viewing numbers. However, little is known regarding how numerical information is represented in children's brains in early elementary school and how their math skills and home math environment (HME) relates to these foundational neurocognitive processes. Here, we measured children's neural activity while viewing symbolic (digits) and nonsymbolic (dot sets) numbers using fMRI, indexed their HME using caregiver report, and measured their math skills using the KeyMath-3 Diagnostic Assessment. We found that, from 5 to 8 years of age, neural activation (1) distinguished between symbolic and nonsymbolic number formats across occipital and temporal cortices; (2) scaled with quantity differently for symbolic and nonsymbolic number formats across the occipital cortex; (3) scaled with quantity differently for symbolic and nonsymbolic number formats depending on children's HME in insula and subcortical regions; and (4) changed with age across left occipital and parietal cortex depending quantity and children's math skills. Across middle childhood, format-dependent number processing and abstract quantity processing is distributed across occipital, temporal, parietal, frontal, and subcortical regions. Moreover, children's home learning experiences and math skills may shape the neurocognitive processes supporting number processing, providing evidence for experience-dependent neuroplasticity.