“The ability to collaborate with different people and create new values” are expected in a globalized society.　In mathematical education, it is important for students to acquire the ability to collaborate with others and create new values or the merits of mathematics.　The curriculum for mathematics is systematic and much of the new learning content is based on what has already been learned.　In other words, fostering the ability to utilize knowledge and skills already learned is an important objective in mathematics.　Finding new values or the merits of mathematics through collaborative learning in comparative discussions of individual opinions expressed in a group problem solving is a driving force to utilize knowledge and skills already learned.　Therefore, this article clarifies the role of mathematics lessons which create new values or merits of mathematics so that students can appreciate them.