An example of galley division from an unpublished 16th century manuscript, *Opus Arithmetica D. Honorati veneti monachj coenobij S. Lauretij*. Honoratus was a Venetian monk, and the manuscript was written in the second half of the 16th century. But the manuscript was copied by a pupil, probably also a monk, who also did the illustrations. His computation “explodes” against a skyline of Venice. An observer raises his hands in amazement at the result. The computation divides 965347653446 by 6543218 and obtains as the answer 147534. This document is Plimpton MS 227, f. 14v.

Another illustration from *Opus Arithmetica* depicts the compound operation necessary to solve a given problem. The multiplication of 16299 by 613 resulting in the product 9991287 can be discerned in the central configuration. In the lower left corner is another galley division. This page is f. 56v.