297 De forfori ad gerovi⁸¹⁶

Item si de rotulis forfori 453 rotulos gerovi facere volueris, describes

for. ger. 13 6     453 \({1 \over 13}\) 209

⁸¹⁷ forforinos sub forforinis, hoc est 453 [V:47r] sub 13, et multiplica⁸¹⁸ 6 per 453 que sunt ex adverso et divide⁸¹⁹ per 13: exibunt rotuli \({1 \over 13}\) 209, ut [S:55r] in hac descriptione ostenditur.

[R:78r] 298 Rursus si de rotulis gerovinis \({1 \over 5}\) \({1 \over 4}\) \({1 \over 3}\) 23 forforinos facere volueris,

for. ger. 13 6 unc. ℞ 1427 \({2~~\phantom{1}4~~\phantom{1}6 \over 5~~12~~12}\) 51 \({1 \over 5}\) \({1 \over 4}\) \({1 \over 3}\) 23

⁸²⁰ describe⁸²¹ gerovinos sub gerovinis, hoc est \({1 \over 5}\) \({1 \over 4}\) \({1 \over 3}\) 23 sub 6, et multiplica 23 per suas virgulas: erunt 1427, que multiplica per 13 et divide⁸²² per 6 et per ruptos. Tamen si vis multiplica summam⁸²³ per 2 ut habeas \({\phantom{1}1~~\phantom{1}0 \over 12~~12}\) in virgula propter uncias et miliarenses: exibunt rotuli forfori \({2~~\phantom{1}4~~\phantom{1}6 \over 5~~12~~12}\) 51, hoc est rotuli 51 et uncie 6 et miliarenses \({2 \over 5}\) 4.