Proceedings of the Twenty Eighth Annual Meeting of the
North American Chapter of the International Group for the

  
   

Psychology of
Mathematics Education

  
   

Mérida, Yucatán, México

  

November 9 to 12, 2006

  
   
Editors
Silvia Alatorre
José Luis Cortina
Mariana Sáiz
Aristarco Méndez
 
   

Universidad Pedagógica Nacional