Ordinal Numbers

Introduction

Ordinal numbers enable us to put things in order. We also use them to say the date.

Construction

To form ordinal numbers in Esperanto, just add the adjective ending -a to the cardinal number in both written and numeric form. Use a dash to connect tens and ones in written form (see table below).

Example:
la 3a de oktobro 2013
1a unua 2a dua 3a tria 4a kvara
40a kvardeka 41a kvardek-unua 42a kvardek-dua 43a kvardek-tria

Ordinal numbers can be accusative (-n) and plural (-j).

Example:
Mi ne vidis la unuan aŭton.I didn’t see the first car.
Tanja kaj mi estis la unuaj, kiuj alvenis al lia festo.Tanja and I were the first to arrive at his party.

The correct ending is also added to ordinal numbers that are written numerically.

Example:
Larissa naskiĝis la 12an de majo 1998.Larissa was born on the 12th of May 1998.

Usage

Use ordinal numbers to say the date.

Example:
Hodiaŭ estas la dek-unua de junio.Today is the 11th of June.
La koncerto okazos je la dek-sepa de januaro.The concert takes place on the seventeenth of January.

Use ordianl numbers to indicate an order.

Example:
Esperanto estas lia dua fremda lingvo.Esperanto is his second language.
Ni loĝas en la dek-kvina etaĝo.We live on the fifteenth floor.