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Practice with the exercises:
Exercise 1

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.

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


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.


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

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.
    - How is the race going?
    - Pedrosa first, Márquez second.
  • With dates, to indicate the specific day of a month.
    - What day is it today?
    - Today is the 7 th of August.
  • To indicate a century or one of the levels in a building (floor).
    This is the best invention of the 19 th century.
    John's room is on the seventh floor.
  • To indicate the anniversary year of something or someone.
    - What are they celebrating?
    - Their fiftieth wedding anniversary.
  • To refer to a king, queen or pope.
    - Who is that woman?
    - 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.


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

The other numbers adopt the ending -th:

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

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

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