Nerida Fay Ellerton (née Gersch, born 1942) is an Australian mathematics educator and historian of mathematics. She is professor of mathematics education at Illinois State University. As well as studying the present state of mathematics education, she and her husband McKenzie A. (Ken) Clements have researched the history of mathematics education, in the process discovering school worksheets in the Harvard Library that are among the oldest known writings of Abraham Lincoln.
Ellerton was born in 1942; her father was a schoolteacher in a small school in the Australian Outback. She completed a Ph.D. in physical and inorganic chemistry in 1966, at the University of Adelaide; her dissertation was The interaction of aminoacridines and aminobenzacridines with DNA.
By the 1980s she worked in mathematics education at Deakin University. She was director of the National Center for Mathematics Education Research from 1992 to 1993, as professor of mathematics education at Edith Cowan University from 1993 to 1997, and as professor and dean of mathematics education at the University of Southern Queensland from 1997 to 2002. While at Edith Cowan University, she also served as editor of the Mathematics Education Research Journal.
Her first husband died in 2001, and Ellerton moved to Illinois State University in 2002. In 2005, she married Clements, another Australian mathematics educator and long-term collaborator; he moved to Illinois State to join her.
Ellerton's books include: