Er mwyn dweud 'the first' byddwn ni'n defnyddio y cynta(f). Ond, fel rhan o'r trefnolion ('ordinals') 'the eleventh / the twenty-first / the thirty-first' byddwn ni'n defnyddio yr unfed.

1st        y cyntaf

11th     yr unfed ar ddeg

21st     yr unfed ar hugain

31st     yr unfed ar ddeg ar hugain

Dylech chi ddysgu y cyntaf i ' yr unfed ar ddeg' (1st - 11th) i ddechrau

Wedyn byddwch chi'n ychwanegu ar hugain at y rhain i wneud 'yr unfed ar hugan' i 'yr unfed ar dded ar hugain' (21st - 31st), e.e.

ail ('second')                ail ar hugain ('twenty second')

trydydd ('third')          trydydd ar hugain ('twenty third') ac ati

Yn olaf, dylech chi ddysgu'r trefnolion rhwng 'y deuddegfed' ac 'yr ugeinfed' (12th - 20th). Y rhai mwyaf anodd yw'r trefnolion hyn.

y cynta(f) is used for the first, but the eleventh, twenty first and thirty first use yr unfed.

1st        y cyntaf

11th     yr unfed ar ddeg

21st     yr unfed ar hugain

31st     yr unfed ar ddeg ar hugain

Learn 1st to 11th to begin with.

You can then add ar hugain to these to get 21st, 22nd  etc.

e.g.      ail (second)           ail ar hugain (twenty second)

trydydd (third)       trydydd ar hugain (twenty third) etc

Finally, learn the numbers between 12 and 20. These are the most difficult.

Yn Saesneg byddwn ni'n talfyrru trefnolion, gan ddefnyddio ffurfiau fel '1st / 2nd / 3rd' ac ati. Yn Gymraeg byddwn ni'n gwneud yr un peth gan ddefnyddio dwy lythyr olaf yr ail air (neu'r tair llythyr olaf ar adegau), er enghraifft, 'cyntaf > 1af'.

Dyma'r ffurfiau talfyredig i gyd:

1af, 2il, 3ydd, 4ydd, 5ed, 6ed, 7fed, 8fed, 9fed, 10fed,  11eg, 12fed, 13eg, 14eg, 15fed, 16eg, 17eg, 18fed, 19eg, 20fed
21– 31 ain

As with the English 1st, 2nd, 3rd etc, the Welsh dates can be shortened for written work using the last 2 or 3 letters of the last word of the number e.g.  cyntaf  >  1af  see below:

1af, 2il, 3ydd, 4ydd, 5ed, 6ed, 7fed, 8fed, 9fed, 10fed, 11eg, 12fed, 13eg, 14eg, 15fed, 16eg, 17eg, 18fed, 19eg, 20fed

21– 31  ain, e.g. 21st - 21ain, 22nd - 22ain, 31st - 31ain.