And yf the nombre be componede,

doublede16
to be doublede8

write a digital that is part of his composicioun, and sette the article to the lift hande, as thus:—

That done, me most double the last save one, and what growethe þerof me most worche as before. And yf a cifre be, touche it not. But yf any nombre shalle be addede to the cifre,

doublede606
to be doublede303

in þe place of þe figure wipede out me most write the nombre to be addede, as thus:—

In the same wise me shalle wirche of alle others. How to prove your answer. And this probacioun:

Doublede618
to be doublede309

If thow truly double the halfis, and truly half the doubles, the same nombre and figure shalle mete, suche as thow labourede vpone first, And of the contrarie.

Chapter VI. Multiplication.