Indiana began experimenting with numbers as a central motif in 1962, both with his Polygon series as well as four paintings featuring the number 8. The latter were the first paintings in which a number appeared alone, unaccompanied by words. In December of that year, he expanded on the idea and began work on two sets of four diamond polygons, Four Numbers Summing 30 and Small Black Diamond Polychrome Numeral Quartet Summing Thirty, both completed in 1963.
Four Numbers Summing 30 was included in the exhibition De A à Z, 1963: 31 peintres américains choisis par the Art Institute of Chicago at the Centre Culturel Américain, Paris; the first time the artist’s work was shown in Europe.