A nice article in Globe and Mail. A random quote:
“We have learned so much about language and learning to read. The same thing needs to happen with math,” said Dr. Ansari, who notes that for every 14 studies on how children learn to read, only one is done on how they grasp math. Dyscalculia is as prevalent as dyslexia, a learning disorder that makes it hard for children to master reading, Dr. Ansari said. But parents, teachers and educational professionals have far less awareness about it.
[with thanks to Dennis Lomas]