They emphasized that in the mid-20th century two theories have dominated mathematics education research, piaget’s information processing model and Vygosky's social-constructivism. Vidakovic and Martin advocated co-constructivism that reconciles both the individualand social aspects of piaget and Vygotsky(Vidakovic & Martin,2004). Viadaok and Martin concluded that mathematics learning can be enhanced by peer-collaboration in small groups, provided there are some common understandings of what counts as a proof.