Lee Gangsuk (F) graduated from Seoul National University of Education, and majored in Elementary Math Education at the graduate school of the same university. Since 2002, Lee has run a website "Math Master" (http://claralee.new21.net) to help children study math in a pleasant and fun way. The website has provided help to many people including elementary teachers and parents of elementary students. Through lectures in professional development programs and teacher consulting, she share her special instruction skill or playing math games.