Illustrating The Nine Chapters on the Mathematical Art - In the Classroom: Rice-huskers and City Walls

Chapter 2, "Millet and Rice"

The focus of Chapter 2, "Millet and Rice," is on exchange rates for rice and millet in various states of preparation. This topic often strikes my students as insignificant. Figure 10 helps me make the point that this is an important part of the Chinese culture. The photograph shows rice being husked, in a brick relief now in the National Museum of China in Beijing. The relief is from the Eastern Han dynasty (25-220 CE), which is particularly nice in that it dates from the same time as the compilation of the Nine Chapters.

Figure 10. This brick relief of rice-huskers from the Eastern Han dynasty (25-220 CE) is in the National Museum of China in Beijing (photo by the author).

Chapter 5, "Construction Consultations"

"Construction Consultations" (Chapter 5) includes volumes of trapezoidal prisms. Rather than being theoretical geometric shapes, such solids are used in the construction of walls of cities such as Xi'an, so the problems are of practical value. Figure 11 depicts a model of the city walls of Xi'an and Figure 12 depicts modern-day city walls.

Figure 11. A cross-section of a model of the wall of Xi'an is on display in the marvelous Shaanxi History Museum. The inside of the wall faces us. (Photo by the author)

Figure 12. In this photograph of part of the present-day wall of central Xi'an, the slanted nature of the wall is apparent. The photographer seen part way down the steps is MAA member and frequent study tour participant, Professor John Wilkins of California State University-Dominguez Hills. (Photo by the author)