Ordinal Numerals:

Here are some basic grammar rules for ordinal numerals:

 

Ordinal numerals are used to express the order or sequence of things, such as first, second, third, etc.

In English, ordinal numerals are generally formed by adding the suffix -th to the cardinal numeral (except for

first , which has its own unique form).

For ordinal numerals ending in y, the y is often changed to i before adding -th.

For example: twenty becomes twentieth, fifty becomes fiftieth.

 

When using ordinal numerals, we generally add the before the number to indicate that it is an ordinal.

For example: the third house on the left or the twentieth century.

 

Ordinal numerals can be used as both adjectives and pronouns.

 As adjectives, they modify nouns (e.g., the fourth book).

As pronouns, they can stand alone to represent a number in a sequence (e.g., the fourth, or he came in third).

 

A table of the ordinal numbers from 1 to 1,000,000: 

Cardinal Number	Ordinal Number
1	1st (first)
2	2nd (second)
3	3rd (third)
4	4th (fourth)
5	5th (fifth)
6	6th (sixth)
7	7th (seventh)
8	8th (eighth)
9	9th (ninth)
10	10th (tenth)
11	11th (eleventh)
12	12th (twelfth)
13	13th (thirteenth)
14	14th (fourteenth)
15	15th (fifteenth)
16	16th (sixteenth)
17	17th (seventeenth)
18	18th (eighteenth)
19	19th (nineteenth)
20	20th (twentieth)
21	21st (twenty-first)
22	22nd (twenty-second)
23	23rd (twenty-third)
24	24th (twenty-fourth)
25	25th (twenty-fifth)
26	26th (twenty-sixth)
27	27th (twenty-seventh)
28	28th (twenty-eighth)
29	29th (twenty-ninth)
30	30th (thirtieth)
31	31st (thirty-first)
32	32nd (thirty-second)
33	33rd (thirty-third)
34	34th (thirty-fourth)
35	35th (thirty-fifth)
36	36th (thirty-sixth)
37	37th (thirty-seventh)
38	38th (thirty-eighth)
39	39th (thirty-ninth)
40	40th (fortieth)
50	50th (fiftieth)
60	60th (sixtieth)
70	70th (seventieth)
80	80th (eightieth)
90	90th (ninetieth)
100	100th (hundredth)
200	200th (two hundredth)
300	300th (three hundredth)
400	400th (four hundredth)
500	500th (five hundredth)
600	600th (six hundredth)
700	700th (seven hundredth)
800	800(eight hundredth)

 

 

 

A table of ordinals from 101 to 1.000.0001,000,000th:

Cardinal Number	Ordinal Number
101	101st (hundred and first)
102	102nd (hundred and second)
201	201st (two hundred and first)
1000	1000th (thousandth)
1001	1001st (thousand and first)
1002	1002nd (thousand and second)
1000000	1,000,000th (millionth)

 

 

 

Definite article The before ordinal numerals:

The grammar rule for using the definite article the before ordinal numbers is as follows:

 

When referring to a specific ordinal number in a sequence or series, the definite article the is used before the ordinal number.

For example: I’m studying for the second exam in the series. (referring to a specific ordinal number in the sequence)

The fifth book in the series is my favorite. (referring to a specific ordinal number in the sequence)

She finished in third place. (referring to a specific ordinal number in a race or competition)

 

However, when using ordinal numbers as general descriptions, the definite article is not usually used.

For example, He’s in first grade this year. (referring to a general description of the grade level)

She’s celebrating her 50th birthday next month. (referring to a general description of the milestone)

 

 

 

The formation of ordinal numerals:

Here are some grammar rules related to the formation of ordinal numerals:

To form ordinal numerals in English, the last two digits of the cardinal number are changed to their ordinal form.

For example: 1 becomes st

2 becomes nd

3 becomes rd

and all others become th

For numbers that end in 1, 2, or 3, except for 11, 12, and 13,

The corresponding suffixes are st, nd, and rd, respectively.

For numbers that end in 11, 12, or 13, the corresponding suffix is th.

For all other numbers, the corresponding suffix is th.

For example:

1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th

11th, 12th, 13th, 14th, 15th, 16th, 17th, 18th, 19th, 20th

21st, 22nd, 23rd, 24th, 25th, 26th, 27th, 28th, 29th, 30th

 

 

 

 

Suffixes for Ordinal Numbers:

As for the suffixes used to form ordinal numerals, they are as follows:

st is used for numbers ending in 1 (except for 11).

nd is used for numbers ending in 2 (except for 12).

rd is used for numbers ending in 3 (except for 13).

th is used for all other numbers.

 

 

 

Spelling change rules:

Here are some rules for spelling change while forming compound and simple ordinal numerals:

For compound ordinal numbers

(e.g., 21st, 22nd, 23rd), the last digit is always used to form the ordinal ending,

 (e.g., 1st, 2nd, 3rd), and the first digit is used to determine the first word in the ordinal (e.g., twenty).

 

When forming simple ordinal numbers

(e.g., 1st, 2nd, 3rd), the ending -y is dropped from numbers ending in

-ty (e.g.  forty becomes fortieth).

 

When forming simple ordinal numbers (e.g., 1st, 2nd, 3rd),

the endings -one, -two, and -three are shortened to -first, -second, and -third, respectively.

(e.g., twenty-one becomes twenty-first).

 

When forming simple ordinal numbers (e.g., 1st, 2nd, 3rd),

the endings -fifth, -eighth, and -ninth drop the f, gh, and n, respectively.

(e.g., fifth becomes fifth, eighth becomes eighth, and ninth becomes ninth).

 

When forming simple ordinal numbers (e.g., 1st, 2nd, 3rd),

the endings -thousand, -million, and -billion drop the -d, -n, and -n, respectively.

(e.g., a thousand becomes a thousandth, million becomes a millionth, and a billion becomes a billionth).

 

 

 Examples:

21st (twenty-first), 22nd (twenty-second), 23rd (twenty-third)

 40th (fortieth), 50th (fiftieth), 60th (sixtieth)

 21st (twenty-first), 32nd (thirty-second), 43rd (forty-third)

 5th (fifth), 8th (eighth), 9th (ninth)

 1000th (thousandth), 1,000,000th (millionth),

1,000,000,000th (billionth)

 

Here are some guidelines for using ordinal numerals with chapters, parts of books, paragraphs, and parts of plays:

 Chapters: When referring to a specific chapter in a book, use the ordinal numeral: (e.g., Chapter three or Chapter 3).

 Parts of books: When referring to a specific part of a book, use the ordinal numeral: (e.g., Part two or Part 2).

 Paragraphs: When referring to a specific paragraph in a text, use the ordinal numeral (e.g., Paragraph 4 or Paragraph Four).

Parts of plays: When referring to a specific part of a play, use the ordinal numeral (e.g., Act 1, Scene 3, or Act One, Scene Three).

 

 

Here are some guidelines for using ordinal numerals with house numbers, rooms, train cars, shoe sizes, and clothing:

 House numbers: When referring to a specific house number on a street, use the ordinal numeral: (e.g., 123rd Street or 123rd).

 Rooms: When referring to a specific room in a building, use the ordinal numeral: (e.g., Room 301 or Room Three-Oh-One).

 Train cars: When referring to a specific train car, use the ordinal numeral (e.g., Car 5 or Car Five).

 Boot sizes: When referring to the size of a pair of boots or shoes, use the ordinal numeral (e.g., size 9 or size Nine).

 Clothing: When referring to clothing sizes, use the ordinal numeral: (e.g., size small or size small).

 

In general, ordinal numerals are used to indicate the order of items in a sequence, so they are useful for identifying specific items within a category, such as a particular house on a street or a specific room in a building.

 

Different countries and regions may use different systems. for sizing shoes and clothing, so it’s important to be aware.

of local conventions and units of measurement.

 

When referring to dates of birth, it is common to use cardinal numbers rather than ordinal numbers.

For example: you would say John was born on December 15, 1990, rather than John was born on December 15th, 1990.

However, when referring to a person’s age,  ordinal numbers are used.

For example, John is celebrating his 31st birthday today.

                

 

Click here to learn more about English Ordinal Numerals

Click here to learn more about English Cardinal Numerals

Click here to learn more about What is a Numeral?