Elementary arithmetic, with brief notices of its history... by Robert Potts.

4
The number Ten thousands is denoted by 10,000.
One hundred thousands by 100,000.
One million by 1,000,000.
Ten millions by 10,000,000.
One hundred millions by 100,000,000.
One thousand millions by 1,000,000,000.
Ten thousand millions by 10,000,000,000.
One hundred thousand millions by 100,000,000,000.1
It is seldom in ordinary calculations that numbers are required
beyond hundreds of thousands of millions.
The principle of the denary notation is not limited, and may be
extended for the expression of numbers of any order. It is therefore
obvious that the denary method of notation may be continued to any
extent, and will suffice for the representation of any number, however
great.
3. Plo T. To dezote by figyees cay given number e xpressed in words;
and eonversely, to express n 'T words anTy giveY n nlumber denoted byfigzres.
[First. Any number expressed in words can be denoted in figures
by writing the figure which denotes the units in the first place, and
the figures which denote the tens, hundreds, thousands, &c., respectively, in the second, third, fourth, &c., places on the left of the first
place, with ciphers in those places where the figure of any order is
wanting.
Conversely. A number denoted by figures can be expressed in
words by first dividing the given number into periods of three or of
six figures each, and writing the values of the figures which are in the
first, second, third, fourth, &c., places as the units, tens, hundreds,
thousands, &c., of which the number is composed.
1 The next unit in order is ten hundred thousand millions, or one thousand
thousand millions, or one million of millions. Instead of considering the orders of
higher numbers as successively formecd by making ten units of one order equivalent to one unit of the next superior order, it has been found convenient to consider large numbers in periods of six figures each. The first period beginning with
unity and extended to six figures is considered the period of units, the secondl
the period of millions, the third the period of millions of millions, and so on, so,
that the units of the first, second, third, &c., periods in order will be as follows:
One, the primary unit denoted by 1.
One million denoted by 1 with 6 ciphers.
One million of millions, or a billion, is denoted by 1 with 12 ciphers.
One million of billions, or a trillion, by 1 with. 1S ciphers.
One million of trillions, or a quadrillion, by 1 with 24 ciphers.
One million of lu.adrillions, or a quintillion, by 1 with 30 ciphers.
One million of quintillions, or a sextillion, by 1 with 36 ciphers.
One million of sextillions, or a septillion, by 1 with 42 ciphers.
One million of septillions, or an octillion, by 1 with 48 ciphers.
One million of octillions, or a nonillion, by 1 with 54 ciphers.
One million of nonillions, or a decillion, by 1 with 60 ciphers; and so on.