Addac adding machine
1926
1926
1921
1926
1927
1920
1920-1925
circa 1927
1920
1924
1925
1928
1925
1922
1927
1923
1924
1925
1921-1926
1924-1927
1922-1923
1922-1923
1922-1923
1922-1923
1927
1927
1923
1920-1925
circa 1920
1926
2000-100 BCE
1920-1928
1924
1934
circa 1920
1955; 1830
1921
1925-1928
before 1928
1928
1920-1928
1923
1928
1925-1927
circa 1920
1926
1920
circa 1927
1920
1925
1926-1928