How to read numbers in English

BASIC NUMBERS

Remember that large numbers are separated by commas: 123,456,789 and decimals need dots: 1.25

MORE DIFFICULT NUMBERS
We don't normally write numbers with words, but it's possible to do this and, of course, this will show how we say the numbers.

In writing large numbers, American English uses a comma ( , ) to separate thousands, millions, etc. American English also uses a hyphen ( - ) to separate "tens" words (twenty, fifty, etc.) and
"ones" words (one, three, six, etc.)

Examples:

written   said
1,011   one thousand eleven
   
21,011   twenty-one thousand eleven
   
721,011   seven hundred twenty-one thousand eleven
 ....................................................................................................................................
1,256,721   one million two hundred fifty-six thousand seven hundred twenty-one
   
31,256,721   thirty-one million two hundred fifty-six thousand seven hundred twenty-one
   
631,256,721   six hundred thirty-one million two hundred fifty-six thousand seven hundred twenty-one
 ....................................................................................................................................
1,492,638,526   one billion four hundred ninety-two million six hundred thirty-eight thousand five hundred twenty-six
   
41,492,638,526 forty-one billion four hundred ninety-two million six hundred thirty-eight thousand five hundred twenty-six
   
941,492,638,526  nine hundred forty-one billion four hundred ninety-two million six hundred thirty-eight thousand five hundred twenty-six
__________________________________________________________________

 NOTES:

1. In American English, the order of large numbers is thousand, million, billion, trillion, etc. (1,000; 1,000,000; 1,000,000,000; 1,000,000,000,000; etc.)
2. In American English a thousand million is a billion, but in British English, a thousand million is a milliard.
3. When saying large numbers, do not make thousand, million, billion, trillion, etc. plural. (WRONG: *twenty thousands dollars; *five millions people; CORRRECT: twenty thousand dollars; five million people)
4. Commas separate thousands, millions, etc. (21,011-31,256,721-941,492,638,526)
5. People often say "a" instead of "one" before hundred, thousand, etc. and they often add "and" before the last number (a hundred and twenty-one / a thousand and eleven)

DIFFERENCE BETWEEN BRITISH AND AMERICAN ENGLISH (from Wikipedia)

	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."
334	"Three hundred and thirty-four."	"Three-thirty-four."	"Three-three-four."

ORDINAL NUMBERS AND FRACTIONS

Ordinal numbers are also used for fractions:

• 1/10 - one tenth
• 3/4 - three quarters
• 15/16 - fifteen sixteenths

SPECIAL NUMBERS

Some numbers have special names in certain contexts:

0:

• Zero: formal scientific usage
• Naught / nought: mostly British usage
• Aught: Mostly archaic but still occasionally used when a digit in mid-number is 0 (as in "thirty-aught-six", the .30-06 Springfield rifle cartridge and by association guns that fire it)
• Oh: used when spelling numbers (like telephone, bank account, bus line [British: bus route])
• Nil: in general sport scores, British usage ("The score is two–nil.")
• Nothing: in general sport scores, American usage ("The score is two–nothing.")
• Null: used technically to refer to an object or idea related to nothingness. The 0th aleph number (\aleph_0) is pronounced "aleph-null".
• Love: in tennis, badminton, squash and similar sports (origin disputed, often said to come from French l'œuf, "egg"; but the Oxford English Dictionary mentions the phrase for love, meaning nothing is at risk)

1:

• Ace in certain sports and games, as in tennis or golf, indicating success with one stroke, and the face of a die, playing card or domino half with one pip
• Birdie in golf denotes one stroke less than par, and bogey, one stroke more than par

2:

• Couple
• Pair
• Eagle in golf denotes two strokes less than par
• Duo

3:

• Trio

6:

• Half a dozen

12: 

• A dozen (first power of the duodecimal base), used mostly in commerce

100:

• A century, also used in cricket scores and in cycling for 100 miles.
• A ton, in Commonwealth English, the speed of 100 mph[5] or 100 km/h.

120:

• A great hundred or long hundred (twelve tens; as opposed to the small hundred, i.e. 100 or ten tens), also called small gross (ten dozens), both archaic

144: 

• A gross (a dozen dozens, second power of the duodecimal base), used mostly in commerce

10100: 

• Googol (1 followed by 100 zeros), used in mathematics; not to be confused with the name of the company Google (which was originally a misspelling of googol)

COMBINATIONS OF NUMBERS IN SPORT

• 1–0    British English: one-nil; American English: one-nothing, one-zip, or one-zero
• 0–0    British English: nil-nil, or more rarely nil all; American English: zero-zero or nothing-nothing, (occasionally scoreless or no score)
• 2–2    two-two or two all; American English also twos, two to two, even at two, or two up.

REFERENCE:

• http://www.studyenglishtoday.net/cardinal-numbers.html
• https://en.wikipedia.org/wiki/English_numerals