The Cardinal Numbers were first exhibited in Indiana’s 1966 “LOVE Show” at the Stable Gallery, New York. A single work composed of ten 60 x 50-inch paintings, its colors, like that of the first LOVE paintings, are red, green, and blue. These colors were inspired by the Phillips 66 stations where the artist’s father worked, specifically the red and green of the Phillips 66 sign against a blue sky. A series of 12 and 24-inch Cardinal Numbers were also exhibited in the show.
In 1967 Indiana was invited to participate in the American Pavilion of the International and Universal Exposition in Montreal. Asked to contribute a very tall painting, he proposed The Cardinal Numbers, which were hung vertically in countdown, measuring over fifty feet high. The following year The Cardinal Numbers were shown in Documenta 4, in Kassel, Germany.
Unlike his earlier 60 x 50 series of numbers, painted between 1964 and 1965, which were broken up and sold individually, The Cardinal Numbers were kept together.