It is problematic that middle school students cannot formulate an equation or represent the situation in a graph in their problem solving, while they can solve the given equation and represent the graph of the given equation solely. Expressions or equations, graphs, and tables should be effective tools for their problem solving. Therefore, it is needed to develop integrated curriculum for Function and Equation. We have edited experimental textbooks as actualized our intended curriculum. In this paper, we insist that it is necessary that the notion of mathematical activity is embedded consistently throughout the curriculum for coordinating the intended curriculum in the implemented curriculum. In many curriculum development studies, the focus devoted to this point is lack or short because of the difficulty of a long-term implementation. Our research emphasizes this point, and thus is intended to develop curriculum through a long-term lesson studies.
