Mary McPike McLaughlin, 86, a retired mathematics teacher who had taught in the public school systems of the District and Montgomery County, died of congestive heart failure Jan. 7 at Suburban Hospital. She lived in Chevy Chase.

She taught in the D.C. public schools from 1934 to 1959. During those years, she taught both business and mathematics classes and served on the faculties of McFarland Junior High, Eastern High, Taft Junior High and Roosevelt High School. She taught math at Walter Johnson High School in Bethesda from 1959 to 1963, then joined the faculty of Walt Whitman High School in Bethesda, from which she retired in 1973 as a mathematics resource teacher.

Mrs. McLaughlin had done volunteer work for the cultural history division of the Smithsonian Institution and for the Christ Child Society. She received a White House award for her volunteer work.

She was a member of the Catholic Shrine of the Blessed Sacrament, the D.C. Historical Society, Columbia Country Club, the Barnard College Alumnae Association, and the Maryland and Montgomery County Retired Teachers associations.

Mrs. McLaughlin was born in Washington and grew up in Brooklyn, N.Y. She was a 1933 mathematics graduate of Barnard College. She received a master's degree in mathematics from Columbia University.

Her husband, Russell L. McLaughlin, died in 1985. Survivors include five sons, Peter, of Fayetteville, Pa., and Old Naples, Fla., Michael, of Alexandria, Arthur, of Falls Church, David, of Las Vegas, and Russell Jr., of Centreville; 14 grandchildren; four great-grandchildren; and a great-great-grandchild.