Christofferson attended the University of Minnesota and earned his A. B. degree, along with membership in Phi Beta Kappa, in only 3 1/2 years. After graduation in 1917, he continued his career as a teacher, principal, and superintendent of schools in several Minnesota communities, including Red Wing. He married his first wife, Christina Gaumnitz, in 1919.
In 1923 Christofferson earned a Master of Arts degree from the University of Chicago and accepted a position as head of the Mathematics Department at Wisconsin State Teachers College in Oshkosh. Five years later he was hired as Professor of Mathematics at Miami University in Oxford, Ohio. In 1935 he assumed the additional duties of Director of Secondary Education, having, in the meantime, earned a Ph.D. from Columbia. Dr. Christofferson held his joint appointment in the Department of Mathematics and the School of Education until his retirement in 1961. He also served briefly as acting director of the McGuffey Laboratory School, acting Director of Admission, and director of student teaching. Following World War II, he served as a specialist in education with the U. S. Army in Florence, Italy, and Wiesbaden, Germany.
Dr. Christoffersonís best known publication is Geometry Professionalized for Teachers, based on his 1933 doctoral dissertation at Columbia. He was an early advocate of an inquiry or heuristic method in teaching mathematics. He also wrote a number of mathematics workbooks and curriculum guides as well as a laboratory manual for aeronautics. He published more than 20 articles and book reviews in professional journals between 1924 and 1938, and he was the mathematics editor of School Science and Mathematics from 1942-45.
Christofferson served on the board of directors of the National Council of Teachers of Mathematics from 1934-38, followed by a term as NCTM President (1938-40). At a meeting in Columbus on November 4, 1950, Christofferson, along with Harold P. Fawcett and eleven other teacher leaders, founded the Ohio Council of Teachers of Mathematics. He served as that organizationís president from 1952-54.
Christofferson was active in Oxford community life, serving as Chair of the Community Chest, President of the Kiwanis Club, an elder and Sunday School superintendent in the Presbyterian Church, and a member of the Masonic Lodge. After retirement, he organized a series of continuing education lectures for adults. He also contributed generously to Miami University, including endowments to establish scholarships and prizes for future mathematics teachers. He died at Rochester, Minnesota, on June 4, 1973.
Article by David E. Kullman