This is the title page of the Summa de arithmetica, geometrica, proportioni et proportionalita, published by Luca Pacioli (1445-1509) in 1494. This was the most comprehensive mathematical text of the time and one of the earliest printed mathematical works. It contained not only practical arithmetic, but also algebra, practical geometry and the first published treatment of double-entry bookkeeping.
This page is the reverse of the title page. A translation of this would be valuable.
On this page (f. 36v) Pacioli illustrates one of the methods of finger counting prevalent at his time in Italy.