In a discovery that could help instructors better teach deaf children, a team of University of Chicago researchers has found that a gesture-sign mismatch made while explaining a math problem suggests that a deaf child is experiencing a teachable moment. Teachers also frequently use their own gestures to help students learn. They can illustrate how numbers in an equation can be grouped, for example, to help students understand how to make both sides of an equation have the same value. The deaf child watching the interpreter will then miss any messages that the teacher sends in gesture and not in