Irish Lesson 43
Irish Lesson 43

The numbering system in Irish differentiates among simple cardinals (either stand-alone numbers, such as occur in mathematics, or numbers giving the quantity of some object) and ordinals, which put objects in some order. This will become clear when you study this lesson.

Counting
These numbers are used in counting, telling time, and when the noun to which they refer goes before them.
a haon
a dó
a trí
a ceathair
a cúig
a sé
a seacht
a hocht
a naoi
a deich
a haon déag
a dódhéag
a trídéag
a ceathair déag
a cúig déag
a sédéag
a seacht déag
a hocht déag
a naoi déag
fiche

Examples of use:
Counting to start a race: a haon, a dó, a trí.
Serially numbered objects: seomra a seacht, bad a sédeag.
Arithmetical work: a tríagus a naoi, sinéa dódheag.
Giving quantities of some object, with the number preceding the noun:
aon bhóamháin, one cow
dhábhó, two cows
tríbhó
ceithre bhó
cúig bhó
sébhó
seacht mbó
ocht mbó
naoi mbó
deich mbó
aon bhódhéag
dhábhódhéag
tríbhódhéag
ceithre bhódhéag
cúig bhódhéag
sébhódhéag
seacht mbódhéag
ocht mbódhéag
naoi mbódhéag
fiche bó

In this use, as you can see, aon, one, aspirates, "two" becomes "dhá" and aspirates, "four" has changed slightly, and from 11 on, there is a "dheag", similar to English "teen", added on. From 1 to 6, the number causes aspiration (where possible), and from 7 to 10, the number eclipses (where possible).
It all sounds complicated, but if you will practice on the lists above, and then try to use the numbers several times a day, say in counting or in reading license plates, one numeral at a time, you will be pleasantly surprised at your facility.
Now for a simpler and often-used help: telling time.
one o'clock -- Táséa haon a chlog
two o'clock -- Táséa dóa chlog
three o'clock -- Táséa tría chlog
four o'clock -- Táséa ceathair a chlog
five o'clock -- Táséa cúig a chlog
six o'clock -- Táséa séa chlog
seven o'clock -- Táséa seacht a chlog
eight o'clock -- Táséa hocht a chlog
nine o'clock -- Táséa naoi a chlog
ten o'clock -- Táséa deich a chlog
eleven o'clock -- Táséa haon déag a chlog
twelve o'clock -- Táséa dódhéag a chlog
What time is it? Cén t-amé?
a good morning, maidin mhaith
good night, oíche mhaith
mid-day, meán lae
mid-night, meán oíche
in the morning, ar maidin
in the afternoon, tráthnóna
at night, san oíche
Days of the week
Monday, An Luan
On Monday, DéLuain
Tuesday, An Mháirt
On Tuesday, DéMháirt
Wednesday, An Chéadaoin
On Wednesday, DéChéadaoin
Thursday, An Déardaoin
On Thursday
Friday, An Aoine
On Friday, DéAoine
Saturday, An Satharn
On Saturday, DéSathairn
Sunday, An Domhnach (DOW-nahk*)
On Sunday, DéDomhnaigh (DOW-nee)