Gripla - 2021, Blaðsíða 94

GRIPLA92
often the first digit also is in the upper number so that equally often those
which follow [15r] it are each in that number which stands over. Set that
digit aligned with the outermost figure which stands under and yet above
both rows. After that take the first from the first figure and each after the
other equally often from the upper number. But if one number is under,
then take it from the upper number. Next move each number that stands
under over by one [place] and find another quotient. Set that by the first
and take the lower number as often from the upper. Do that the same way
as often as needed. If you are not able to find the lower number or figure
in the upper, then set the foremost digit which stands underneath next to
the first and others in same way to the right and then find the quotient in
such a way, and move along the figures as needed. And write each of the
quotients together above so many as needed. But if a cipher stands under,
then skip over it because one cannot divide by that. Then when you come
under the outermost figure and have divided it, you can no longer divide
and then be careful to observe that number which remains, if it is anything.
If you want to prove whether you have divided correctly, then multiply
that number which stood under with the quotient and you will get the
same number that you had at first. And if something remained after the
division, then add that afterwards to what is multiplied and you will find
the same number.
When you take any number and multiply it by itself, that is called a
square, or a quadrate, and the first number which you multiply is called a
root. Each number is the root of some number, but not every number is a
square. If you want to find the root of some number, then first write such
number as you like. And in the first place, which is odd, write under it the
digit which you multiplied by itself, and take from that which is above or
such as comes next to it. After that you double that same digit and that is
called a duple. Then take away the digit and that is called subduple. Note
the subduple and write the duple in the next place if it is a digit, but if it
is an article write it where the digit stood formerly and set a cipher before
it, or else a digit if it is a compound number. After that find a new digit,
multiply it with the duple, and take from the upper number that number
which you multiplied. After that multiply the digit by itself and take that
number from the upper aligned over it. Then next double the digit, note it
together with the former subduple, and set the duple in the next place as