EXAMP. How much sterling money is equivalent to 3390 pezzos 16 soldi of Genoa, exchange at 51\frac{1}{2}d. sterling per pezzo?

Sold. d. Pezz. soldi.
If 20 : 51\frac{1}{2} :: 3390 16
8 20
415
160 67816
415
339080
67816
271264
L. s. d.
160) 28143640 (175897\frac{1}{2} = 732 18 1\frac{1}{2}
Z. z. 2

Exchange. If sterling money be given, it may be reduced or changed into pezzos of Genoa, by reversing the former operation.

Exchange money is reduced to lire money, by being multiplied by 5\frac{1}{2}, as follows:

Pezz. soldi. Decimally.
3390 16 3390.8
5\frac{1}{2} 5.75
16054 0 169540
\frac{1}{2} = 1695 8 237336
\frac{1}{4} = 847 14 169540

Lires 19497 2 Lires 19497.100
And lire money is reduced to exchange money by dividing it by 5\frac{1}{2}:

In Milan, 1 crown = 80
In Naples, 1 ducat = 86
In Leghorn, 1 piastre = 20
In Sicily, 1 crown = 127\frac{1}{2}
12 Denari } make 1 soldi s. d. Ster.
20 Soldi 1 piastre = 4 6

Books and accounts are kept in piastres, soldi, and denari. The piastre here consists of 6 lires, and the lire contains 20 soldi, and the soldi 12 denari; and consequently exchange money is 6 times better than lire money. The course of exchange is from 48d. to 58d. sterling per piastre.