Q&A: What makes math hard?

Daniel Ansari studies how children learn math. The Western University psychologist Canada Research Chair in developmental cognitive neuroscience holds a Steacie Fellowship.
He focuses on the earliest years of school, and we asked him about kids and math.
When does math difficulty appear?
He says the divide begins in junior and senior kindergarten: 
“A lot of our research shows that (these) children’s understanding — being able to name Arabic numerals, being able to compare