This paper explains the development of a wooden puzzle containing wooden joints designed to teach elementary school students how to calculate volume. An experiment was performed with the puzzle, which is a cube with wooden joints, targeting 1st-grade students. The shape of the puzzle is known to be difficult for children to work with. Next, we introduce the results of a test of volume calculation designed for children and describe the methods used to teach volume calculation in Japan. Finally, we compare the concepts of volume calculation and how to create a three-dimensional object in 3D-CAD to reveal that the ideas are almost identical.