Numbers

1 aon
2 dà
3 trì
4 ceithir
5 còig
6 sia
7 seachd
8 ochd
9 naoi
10 deich

In Gaelic aon often lenites: aon thaigh (one house)
Dà lenites for dual marking: dà thaigh (two houses)
Plural starts at trì and the most common plural suffix is -an/-ean: trì taighean (three houses)

When numbering things or when counting, put 'a' before the numbers:

a h-aon
a dhà
a trì
a ceithir
a còig
a sia
a seachd
a h-ochd
a naoi
a deich

Ex: page 8 = duilleag a h-ochd
duilleag = page

You can listen to the numbers 1-10 here: http://www.scottishradiance.com/galphr/galphr9803.htm
or the numbers 1-20 here (click on aireamhan (aireamhan = numbers)): http://www.edu.pe.ca/gray/class_pages/rxmacdonald/gaelicclass/classindex.html