The purpose of the study is to investigate how children's mathematical knowledge is promoted in interaction with the environment and how the environment is important for children's mathematical learning from a socio-cultural perspective. The intention is also to consider pedagogue’s views on the environment and how they work with mathematics in everyday life. The methodological approach is qualitative, and all data collection is collected through qualitative method. The survey was conducted at three different preschools using observations and interviews. What was observed was the children and pedagogues who were in the environment. The result shows that children learn math when interacting with the environment, all material does not have to be mathematical, but it becomes mathematical when it invite mathematical thinking. The pedagogues see the environment as the third pedagogue which relates to Reggio Emilia philosophy. In this philosophy, the environment is referred as the third pedagogue. The pedagogues are of great importance as it is important that they raise and visualize mathematics in everyday life.