A second effort to identify mathematics useful in teaching examines actual teaching.
By watching classroom teaching with an eye for routine activities where mathematical
knowledge would make a difference, researchers expose mathematical issues that
matter for teaching. For example, Hyman Bass and colleagues at the University of
Michigan have found that knowledge of mathematical definition arises more often
and in more ways than one might at first suspect. Besides being terms to memorize,
definitions have a place in classroom mathematical work similar to their place in
mathematics research. A classroom discussion about whether the sum of two odd
numbers is even or odd may break down because a teacher fails to recognize that
students are reasoning from different definitions. Or, if communication becomes
strained as students talk about a new idea, a label and a clear statement of what
is meant might help. This work offers insights