This course is focusing on developing mathematical thinking skills, creativity, and imagination through playful and artistic multidisciplinary activities in early childhood education. Creating equal preconditions for every children’s holistic growth is one of the main goals of Finnish Early Childhood Education Curriculum. In this holistic perspective, the early development of mathematical thinking is embedded in playful and creative, often artistic processes. Individual and community activities, which are stimulating imagination and opening up self-expression and reflection, are providing motivation for the early age improvement of various mathematical skills. The phenomenon-based foundations of mathematical thinking are laid down in early childhood education as part of the advancement of the transversal competences in multidisciplinary educational settings. As transversal competencies consist of knowledge, skills, values, attitudes, and will, the basic mathematical concepts, notions, and principles are also to be discovered by the children in various matters and phenomena, and to be addressed on appropriate cognitive levels. These goals are fully in line with the recent policy development in the European Union, which prioritize the development of key competences and extends STEM to STE-A-M especially by integrating Science, Technology, Engineering, Art and Mathematics (STEAM) and suggesting, that “the earlier people acquire STEAM skills, the better their chances of future educational and professional success will be.