'Little Professor' electronic calculator, 1980
1980
1980
1965-1975
1930-1945
1911-1930
1911-1930
1921-1940
1945-1965
1851-1900
1955-1960
circa 1970
1930-1950
1910-1950
circa 1964
circa 1962
circa 1965
1968
1876
1950-1959
1900-1930