Here Begins the Third Chapter on the Addition of Whole Numbers

Abstract

Moreover with any numbers, no matter how many one will wish to add, one writes them in a table according to that which we said before with the multiplication of numbers, that is the first places of all the numbers that one will wish to add below the first place of the numbers which one placed together for the addition. And the second below the second, and one after the other which follow. And then one begins to add in the hands the figures of the first places of all the numbers that were placed together for the addition, from the lower number up to the higher, ascending; one therefore puts the units above the first place of the numbers, and keeps the tens in hand; to these tens one adds above the numbers which exist in the second places, and one puts the units above the second place, and again one keeps the tens. With them one adds above the sum of the third places of the numbers, and thus putting the units, and keeping the tens, [p19] step by step adding the numbers, one can have the sum of all the numbers without end. And in order to perceive better the additions of two numbers, and even a third, and even more, are shown.