English numerals

English number words include numerals and various words derived from them, as well as a large number of words borrowed from other languages.

Cardinal numbers

s refer to the size of a group. In English, these words are numerals.

0	zero	10	ten
1	one	11	eleven
2	two	12	twelve	20	twenty
3	three	13	thirteen	30	thirty
4	four	14	fourteen	40	forty
5	five	15	fifteen	50	fifty
6	six	16	sixteen	60	sixty
7	seven	17	seventeen	70	seventy
8	eight	18	eighteen	80	eighty
9	nine	19	nineteen	90	ninety

If a number is in the range 21 to 99, and the second digit is not zero, the number is typically written as two words separated by a hyphen.

21	twenty-one
25	twenty-five
32	thirty-two
58	fifty-eight
64	sixty-four
79	seventy-nine
83	eighty-three
99	ninety-nine

In English, the hundreds are perfectly regular, except that the word hundred remains in its singular form regardless of the number preceding it.

100	one hundred
200	two hundred
...	...
900	nine hundred

So too are the thousands, with the number of thousands followed by the word "thousand". The number one thousand may be written 1 000 or 1000 or 1,000; larger numbers are written for example 10 000 or 10,000 for ease of reading. European languages that use the comma as a decimal separator may correspondingly use the period as a thousands separator. As a result, some style guides recommend avoidance of the comma as either separator and the use of the period only as a decimal point. Thus one-half would be written 0.5 in decimal, base ten notation, and fifty thousand as 50 000, and not 50.000 nor 50,000 nor 50000.

1,000	one thousand
2,000	two thousand
...	...
10,000	ten thousand or a myriad, which usually means an indefinitely large number.
11,000	eleven thousand
...	...
20,000	twenty thousand
21,000	twenty-one thousand
30,000	thirty thousand
85,000	eighty-five thousand
100,000	one hundred thousand or one lakh '
999,000	nine hundred and ninety-nine thousand ' nine hundred ninety-nine thousand ' nine lac ninety-nine thousand '
1,000,000	one million or ten lacs '
10,000,000	ten million or one crore '

In American usage four-digit numbers are often named using multiples of "hundred" and combined with tens and ones: "eleven hundred three", "twelve hundred twenty-five", "forty-seven hundred forty-two", or "ninety-nine hundred ninety-nine". In British usage, this style is common for multiples of 100 between 1,000 and 2,000 but not for higher numbers.
Many people pronounce four-digit numbers with non-zero tens and ones as pairs of two-digit numbers without saying "hundred" and inserting "oh" for zero tens: "twenty-six fifty-nine" or "forty-one oh five". This usage probably evolved from the distinctive usage for years; "nineteen-eighty-one", or from four-digit numbers used in the American telephone numbering system which were originally two letters followed by a number followed by a four-digit number, later by a three-digit number followed by the four-digit number. It is avoided for numbers less than 2500 if the context may mean confusion with time of day: "ten ten" or "twelve oh four".
Intermediate numbers are read differently depending on their use. Their typical naming occurs when the numbers are used for counting. Another way is for when they are used as labels. The second column method is used much more often in American English than British English. The third column is used in British English but rarely in American English. In other words, British English and American English can seemingly agree, but it depends on a specific situation.

	Common British vernacular	Common American vernacular	Common British vernacular
	"How many marbles do you have?"	"What is your house number?"	"Which bus goes to the High Street?"
101	"A hundred and one."	"One-oh-one." Here, "oh" is used for the digit zero.	"One-oh-one."
109	"A hundred and nine."	"One-oh-nine."	"One-oh-nine."
110	"A hundred and ten."	"One-ten."	"One-one-oh."
117	"A hundred and seventeen."	"One-seventeen."	"One-one-seven."
120	"A hundred and twenty."	"One-twenty."	"One-two-oh", "One-two-zero."
152	"A hundred and fifty-two."	"One-fifty-two."	"One-five-two."
208	"Two hundred and eight."	"Two-oh-eight."	"Two-oh-eight."
394	"Three hundred and ninety-four."	"Three-ninety-four."	"Three-ninety-four." or "Three-nine-four."

Note: When a cheque is written, the number 100 is always written "one hundred". It is never "a hundred".
In American English, many students are taught not to use the word and anywhere in the whole part of a number, so it is not used before the tens and ones. It is instead used as a verbal delimiter when dealing with [|compound numbers]. Thus, instead of "three hundred and seventy-three", "three hundred seventy-three" would be said. Despite this rule, some Americans use the and in reading numbers containing tens and ones as an alternative.

Very large numbers

For numbers above a million, there are three main systems used to form numbers in English. These are:

the long scale – designates a system of numeric names formerly used in British English, but now obsolete, in which a billion is used for a million million ; and a thousand million is sometimes called a milliard. This system is still used in several other European languages. There is some favour for this scale in astronomy, due to the issue of the vastness of the Universe.
the short scale – always used in American English and almost always in British English since the politically ordained formal adoption of this scale in the 1970s – designates a system of numeric names in which a thousand million is called a billion, and the word milliard is not used.
the Indian numbering system, used widely across Indian subcontinent.

Many people have no direct experience of manipulating numbers this large, and many non-American readers may interpret billion as 10¹² ; moreover, usage of the "long" billion is standard in some non-English-speaking countries. For these reasons, defining the word may be advisable when writing for the public.

Number notation	Power notation	Short scale	Long scale	Indian English
1,000,000	10⁶	one million	one million	ten lakh
1,000,000,000	10⁹	one billion a thousand million	one milliard a thousand million	one hundred crore
1,000,000,000,000	10¹²	one trillion a thousand billion	one billion a million million	one lakh crore
1,000,000,000,000,000	10¹⁵	one quadrillion a thousand trillion	one billiard a thousand billion	ten crore crore
1,000,000,000,000,000,000	10¹⁸	one quintillion a thousand quadrillion	one trillion a million billion	ten thousand crore crore
1,000,000,000,000,000,000,000	10²¹	one sextillion a thousand quintillion	one trilliard a thousand trillion	one crore crore crore

The numbers past one trillion in the short scale, in ascending powers of 1000, are as follows: quadrillion, quintillion, sextillion, septillion, octillion, nonillion, decillion, undecillion, duodecillion, tredecillion, quattuordecillion, quindecillion, sexdecillion, septendecillion, octodecillion, novemdecillion and vigintillion. The highest number in this series listed in modern dictionaries is centillion, which is 10 to the 303rd power. The interim powers of one thousand between vigintillion and centillion do not have standardized names, nor do any higher powers, but there are many ad hoc extensions in use. The highest number listed in Robert Munafo's table of such unofficial names is milli-millillion, which was coined as a name for 10 to the 3,000,003rd power.
The googolplex was often cited as the largest named number in English. If a googol is ten to the one hundredth power, then a googolplex is one followed by a googol of zeros. There is the coinage, of very little use, of ten to the googolplex power, of the word googolplexplex.
The terms arab, kharab, padm and shankh are more commonly found in old books on Indian mathematics.
Here are some approximate composite large numbers in American English:

Quantity	Written	Pronounced
1,200,000	1.2 million	one point two million
3,000,000	3 million	three million
250,000,000	250 million	two hundred fifty million
6,400,000,000	6.4 billion	six-point four billion
23,380,000,000	23.38 billion	twenty-three-point three eight billion

Often, large numbers are written with half-spaces or thin spaces separating the thousands instead of commas—to ensure that confusion is not caused in countries where a decimal comma is used. Thus, a million is often written 1 000 000. In some areas, a point may also be used as a thousands separator, but then the decimal separator must be a comma. In English the point is used as the decimal separator, and the comma as the thousands separator.