Biographical Note
Nerida Fay Ellerton (née Gersch) and McKenzie Alexander "Ken" Clements were professors of mathematics at Illinois State University.
Ellerton earned Ph.D.s in both physical chemistry (University of Adelaide) and mathematics education (Victoria University of Wellington). Clements earned a Ph.D. in mathematics from the University of Melbourne. Each taught at multiple Australian universities before immigrating to the United States, and from 1997 to 2004, Clements taught at the Universiti Brunei Darussalam. Ellerton served as a professor of mathematics education at Illinois State University from 2002 until her retirement to professor emeritus in 2018. Clements served as a professor in the mathematics department at ISU from 2005 until his retirement to professor emeritus in 2019.
Ellerton and Clements married in 2005. As research collaborators, they published together Rewriting the History of School Mathematics in North America, 1607-1861: The Central Role of Cyphering Books (New York: Springer, 2012), Abraham Lincoln's Cyphering Book and Ten other Extraordinary Cyphering Books (New York: Springer, 2014), and Thomas Jefferson and His Decimals, 1775-1810: Neglected Years in the History of U.S. School Mathematics (New York: Springer, 2015), as well as various articles.