Baseball uniform
Numbers were first added to uniforms by the Cleveland Indians in 1916. In 1929, numbers were first added on the backs of baseball uniforms by the New York Yankees and the Cleveland Indians baseball teams. By the 1930s, it was normal for baseball uniforms to have numbers on them. The Yankees were one of the first baseball teams to wear uniform numbers.  This was because of their normal position in the New York Yankee's batting order (Babe Ruth 3, Lou Gehrig 4, etc.).