The present article continues an earlier analysis of occurrences of two algebraic unknowns in the writings of Fibonacci, Antonio de’ Mazzinghi, an anonymous
Florentine abbacus writer from around 1400, Benedetto da Firenze, and another anonymous Florentine writing some five years before Benedetto, and Luca Pacioli.
The following article investigates how Benedetto da Firenze explores in 1463 the use of four or five algebraic unknowns in symbolic calculations, describing it afterwards in rhetorical algebra; in this way he thus provides a complete parallel to what was so far only known from Johannes Buteo’s Logistica from 1559. It also discusses why Benedetto may have seen his innovation as a merely marginal improvement compared to techniques known from Fibonacci’s Liber abbaci, therefore omitting to make explicit that he has created something new.