Ordinal numbers

Vocabulary

1. Ordinal numbers

Ordinal numbers indicate the position that an element occupies within an ordered series. These numbers can be expressed in words (first, second...) or in an abbreviated form (1st, 2nd...)

2. One-digit numbers

The first three numbers have the endings -st, -nd, -rd.

IMG UNIT 30-1

However, from the fourth onwards, we will take the cardinal number and we will add the ending -th to it.

CARDINAL NUMBER
IMG UNIT 30-2
ORDINAL NUMBER
IMG UNIT 30-3

3. Aspects to be taken into account

In the tens ending in zero, the -y is replaced by an -i and then the ending -eth is added.

CARDINAL NUMBER
IMG UNIT 30-4
ORDINAL NUMBER
IMG UNIT 30-5

In the tens containing numbers 1, 2 and 3 we will add the ordinals first, second and third to them respectively.

CARDINAL NUMBER
IMG UNIT 30-6
ORDINAL NUMBER
IMG UNIT 30-7
Numbers 11, 12 and 13 do not follow the same pattern. They end in -th:
I live on the eleventh floor.
Her birthday is on twelfth of August.

4. How are ordinal numbers used?

  • To define the position of an element within a sequential order.
    IMG UNIT 30-8
    - How is the race going?
    IMG UNIT 30-9
    - Pedrosa first, Márquez second.
  • With dates, to indicate the specific day of a month.
    IMG UNIT 30-10
    - What day is it today?
    IMG UNIT 30-11
    - Today is the 7 th of August.
  • To indicate a century or one of the levels in a building (floor).
    IMG UNIT 30-12
    This is the best invention of the 19 th century.
    IMG UNIT 30-13
    John's room is on the seventh floor.
  • To indicate the anniversary year of something or someone.
    IMG UNIT 30-14
    - What are they celebrating?
    IMG UNIT 30-15
    - Their fiftieth wedding anniversary.
  • To refer to a king, queen or pope.
    IMG UNIT 30-16
    - Who is that woman?
    IMG UNIT 30-17
    - Elizabeth II   Elizabeth the Second.
 When we refer to kings, queens and popes in written, we usually use roman numerals, but we pronounce them like an ordinal number.

Remember!

The first three numbers have the endings -st, -nd and -rd:

IMG UNIT 30-18

The other numbers adopt the ending -th:

IMG UNIT 30-19

It should be noted that the tens ending in zero adopt the -ieth ending:

IMG UNIT 30-20

Numbers containing units 1, 2, 3 will keep the endings first, second and third respectively:

IMG UNIT 30-21

Except for numbers 11, 12 and 13, which follow the pattern below:

IMG UNIT 30-22