Cardinal numbers in English

You cardinal numbers (cardinal numbers) are used to designate quantities.

Number	Cardinal number in Portuguese	Number	Cardinal number in Portuguese
0	zero	80	eighty
1	one	81	eighty-one
2	two	82	eighty-two
3	three	90	ninety
4	four	93	ninety
5	five	94	ninety-four
6	six	95	ninety-five
7	seven	100	one hundred
8	eight	113	a/one hundred (and) thirteen
9	nine	187	a/one hundred (and) eighty-seven
10	ten	200	two hundred
11	eleven	235	two hundred (and) thirty-five
12	twelve	287	two hundred (and) eighty-seven
13	thirteen	300	three hundred
14	fourteen	350	three hundred (and) fifty
15	fifteen	390	three hundred (and) ninety
16	sixteen	400	four hundred
17	seventeen	403	four hundred (and) tree
18	eighteen	462	four hundred (and) sixty-two
19	nineteen	500	five hundred
20	twenty	515	five hundred (and) fifteen
21	twenty-one	567	five hundred (and) sixty-seven
26	twenty-six	589	five hundred (and) eighty-nine
30	thirty	600	six hundred
33	thirty-three	661	six hundred (and) sixty-one
35	thirty-five	699	six hundred (and) ninety-nine
40	forty	700	seven hundred
42	forty-two	770	seven hundred (and) seventy
47	forty-seven	773	seven hundred (and) seventy-three
50	fifty	800	eight hundred
54	fifty-four	820	eight hundred (and) twenty
59	fifty-nine	834	eight hundred (and) thirty-four
60	sixty	900	nine hundred
68	sixty-eight	935	nine hundred (and) thirty-five
61	sixty-one	988	nine hundred (and) eighty-eight
70	seventy	1,000	a/one thousand
76	seventy-six	1,003	a/one thousand (and) three
78	seventy-eight	2,000	two thousand

other cardinal numerals

• 1,000,000: the million or one million
• 1,000,000,000: the billion or one billion
• 1,000,000,000,000: the trillion or one trillion

Particulars of Cardinal Numbers in English

When to use "a/an" or "one"

When specifying unit quantity before hundreds or thousands, you can use either "a/an" or "one".

Examples:

• I've said the same thing the hundred times and they still didn't get it. (I already said the same thing hundred times and they still don't understand.)
• I've said the same thing one hundred times and they still didn't get it. (I already said the same thing hundred times and they still don't understand.)

Note that in the sentence above there was no change in meaning regardless of the use of "one" and "a".

Hundred is the word used to indicate hundreds. What defines the number of hundreds is the word used before it. In English "a" is an indefinite article and can mean "a" or "an".

The same is true for the word "thousand" (thousand). Watch the music excerpt A thousand miles, by Christina Perri:

I have died everyday, waiting for you
Darling, don't be afraid, I have loved you for a thousand years
I'll love you for a thousand more

IMPORTANT: before hundred and thousand use up The or one, but when the next word is a noun, it must always be inflected plural.

Note that in the music excerpt played above, the word years (years) is a noun and is inflected in the plural. In the last sentence, the word more (more) is not a noun, but a pronoun.

Use of "and" between numerals

In English, the use of the word and (e) writing the numerals in full is optional.

Examples:

• 9.852: nine thousand, eight hundred fifty-two or nine thousand and eight hundred and fifty-two.
• 21.720: twenty-one thousand, seven hundred twenty or twenty-one thousand and seven hundred and twenty
• 456: four hundred fifty-six or four hundred fifty-six

IMPORTANT: the word "and" is not used between ten and unit. The numeral 38, for example, is written thirty-eight.

When to use "." or","

In English, as a general rule, it can be said that the use of semicolons is the opposite of that used in Portuguese. That is, when the comma is used in Portuguese, the period is used in English and vice versa. Let's look at some cases.

Examples:

• there are 1,000 books on that shelf. (There is 1.000 books on that shelf.)
• There was an increase of 1.5% in the prices. (There was an increase in 1,5% in prices.)

Pronunciation of "-teen" and "-ty"

The suffix -teen is used from numeral 13 to 17:

• 13: thirteen
• 14: fourteen
• 15: fifteen
• 16: sixteen
• 17: seventeen

Already the suffix "-ty" is used in the families of numerals 50, 60, 70, 80, and 90.

• 50: fifty
• 60: sixty
• 70: seventy
• 80: eighty
• 90: ninety

See how to pronounce each of the suffixes:

• -ty /tí/
• -teen /tíin/

Phone numbers

Phone numbers are usually spoken one by one. However, there are two particularities:

• Zero is usually read as "oh" /or/.
• When a number is repeated consecutively, it is common to use the word double before the numeral.

Examples:

• 2401-65 99: two four oh one, sixty-five, double nine
• 3321-77 30: double three two one, double seven, three oh

To learn more about using numbers in English, see also:

• Numbers in English
• Ordinal numbers
• Date in English
• Hours in English