The Ground of Arts
's Arithmetic: or, The Ground of Arts was one of the first printed English textbooks on arithmetic and the most popular of its time. It introduced the equals sign. It was preceded only by two anonymous texts in 1537 and 1539; The Ground of Arts appeared in London in 1543, and it was reprinted around 45 more editions until 1700. Editors and contributors of new sections included John Dee, John Mellis, Robert Hartwell, Thomas Willsford, and finally Edward Hatton.
