Esperanto Numbers: Counting With Nine Roots, No Exceptions

Learn nine roots plus dek, cent and mil, and one spelling rule joins them into every number in Esperanto. Tens and hundreds join (dudek, twenty); everything else stays apart (dek du, twelve). Nothing is irregular.

Ninety-seven is naŭdek sep, nine-ten seven, where French needs quatre-vingt-dix-sept and English hides the ten inside eleven and twelve.

The whole vocabulary

• unuone
• dutwo
• trithree
• kvarfour
• kvinfive
• sessix
• sepseven
• okeight
• naŭnine
• dekten

That is the list. Every number up to 999,999 is built from these:

• Mi havas du librojn. - I have two books.
• Ŝi estas dek jarojn aĝa. - She is ten years old.

Zero

Nul is the numeral; nulo is the noun, for zero as a thing:

• nul ok du - zero eight two (a code, read digit by digit)
• La temperaturo estas sub nulo. - The temperature is below zero.

Saying them

Esperanto spelling is phonetic, so the only traps are letters English reads differently:

The join rule

Two operations, two spellings:

Dudek du is a joined ten and a separate unit in one breath; after that, the number line writes itself. In a sentence:

• Ŝi havas dudek du jarojn. - She is twenty-two. (literally: has twenty-two years)

The join happens only with dek and cent. Mil always stays a separate word, because almost anything can stand in front of it (tricent tridek tri mil, 333,000):

• du mil - 2,000 (PMEG counts dumil as a misspelling)
• dek du mil - 12,000

The popular shortcut, "multiplication joins, addition stays apart", is right everywhere except here.

The number line from 11 to 1,000

Every ten and hundred, written out. Each one is the join rule applied once.

The teens and the tens

The hundreds

They do not decline

Cardinals take no -j and no -n. The noun takes both; the number sits still:

• tri libroj - three books
• Mi vidas tri librojn. - I see three books.

If your first language puts endings on numbers, this is the habit to drop, and nothing replaces it. The one exception is unu as a pronoun rather than a count:

• la unuj kaj la aliaj - the ones and the others

Words built from numbers do decline, because they are no longer numbers. An ordinal is an adjective; miliono is a noun:

• la unuajn tagojn - the first days (as an object)
• du milionoj - two million

Thousands, millions and billions

Mil is a numeral like cent: no ending, no da. Unlike cent, it stays apart from the number in front of it:

Above that the words are nouns ending in -o: miliono (a million) and miliardo (a billion). Like any noun they take the plural and object endings, and they link to what they count with da:

• unu miliono da homoj - a million people
• Ili vendis tri milionojn da libroj. - They sold three million books.

The -n goes on milionojn, the object. Libroj stays plain, because da is a preposition and shields the noun behind it. A big number mixes both systems:

• du milionoj kvincent mil - 2,500,000

Ordinals: add -a

Any number plus the adjective ending -a is an ordinal:

A compound is usually joined with a hyphen so the -a clearly covers the whole number; la dek dua written apart is also correct. Ordinals agree like adjectives and tell the time:

• la unua tago - the first day
• Je la tria. - At three o'clock.

Swap -a for -e and you get the adverb:

• Unue, mi ne scias. - Firstly, I do not know.

Fractions, multiples and groups are built the same way, with suffixes: see fractions, multiples and groups.

Numbers and da

A bare numeral is complete on its own: tri libroj, never tri da libroj. Only a number noun links with da:

• tri libroj - three books
• dekduo da ovoj - a dozen eggs
• miloj da homoj - thousands of people

The full da rule, with multe da and glaso da, is in quantity.

Mistakes English speakers make

What to do next

1. Read your phone number aloud in Esperanto, digit by digit.
2. Say this year and the year you were born.
3. Then read fractions, multiples and groups.

See also

• Fractions, multiples and groups - duono, duobla, duope and po.
• Quantity - iom, multe, kelkaj and the da rule in full.
• Time expressions - numbers at work in clock times and dates.