Debates about children’s understanding of mathematics has focused on how children make use of school mathematics in their every day lives. The notion of numeracy has been gaining increasing currency is recent curriculum reforms that support the need for mathematics and mathematics teaching to pay attention to involving children in the learning of mathematics in ways that will make sense to each child. Children’s everyday life abounds with mathematics objects and concepts. An awareness .of the mathematics in the environment is a function of students’ ability to interpret the relevance of both the formal and informal mathematics they have been experiencing in the classroom. Regardless of the context in which children engage with mathematics, children’s ability to reason and make decision with mathematics provide teachers insight into developments in children's understanding. These understandings are built on children’s personal experiences, intuitions and formal knowledge taught in the classroom.