Ceacht 20:
clog	a clock	n. m1	
cén t-am é	what time is it?	[question word] + [n. m1 #prefix# ] + [pron.]	
a haon a chlog	1 o'clock	[part.] + [n. m1  #prefix# ] + [part.] + [n m1]	
a haon	1	[part. ] + [n. m1  #prefix#]	
a dó	2	[part. ] + [n. m4]	
a trí	3	[part. ] + [n. m4]	
a ceathair	4	[part. ] + [n. m4]	
a cúig	5	[part. ] + [n. m4]	
a sé	6	[part. ] + [n. m4]	
tá sé a haon a chlog	it is one o'clock	[v.]+[pron.]+[part.] +[n. m1 : #prefix#] + [part.] + [n m1]	
mall	late, slow	adj.	
seo duit	here you are	[determiner ] + [per. prep.]	
mórán daoine	many people	[n. m1] + [ n. m4]	
lán	full	adj.	

The cardinal numbers, for example those numbers used when telling the time, are as follows:
0	= náid
1	= a haon
2	= a dó
3	= a trí
4	= a ceathair
5	= a cúig
6	= a sé
7	= a seacht
8	= a hocht
9	= a naoi
10	= a deich

"0", "7", "8", "9" and "10" are included in this list, although these numbers don't appear in this lesson, to illustrate the point that one uses the particle a before the number (with the exception in this case of náid) and this little particle prefixes h to a number beginning with a vowel.

aon and ocht are one and eight respectively but, because of that prefix h, they become "a haon" and "a hocht"

This number system is also used, for example, in reciting a telephone number.  For example, the telephone number 0128 456 7898 would be recited as "náid, a haon, a dó, a hocht, a ceathair, a cúig, a sé, a seacht, a hocht, a naoi a hocht."