Learn Spanish Numbers - Patterns & Rules

Two ways to count in Welsh

Welsh counts two ways, and a learner needs both. The decimal system — degol — (un deg un, dau ddeg pump) is what schools teach today. The traditional system — ugeiniol, from ugain, twenty — counts in twenties (un ar ddeg, ugain, deugain), and it is not archaic trivia: for the time, for dates and for age it is the only option. Those two Welsh words are what the toggle on the practice page is labelled with.

Which one you reach for depends on what you are talking about:

Situation	System	Example
Arithmetic, counting aloud	Decimal	un deg naw plys chwech
Telling the time	Traditional, always	chwarter i ddeuddeg
Dates (day of the month)	Traditional ordinal, always	yr ail ar hugain o fis Medi, written 22ain
Age and durations	Traditional	ugain mlynedd
Money	Mostly decimal, but certain amounts have fixed traditional forms	hanner can punt (£50), chweugain (once ten shillings, later slang for 50p)
Everything else	Decimal	—

On courses the traditional forms arrive early and in pieces — ugain turns up at Mynediad level through telling the time, and ordinals such as trydydd ar ddeg at Sylfaen — so it is worth meeting them from the start rather than treating them as an advanced topic.

What this drill covers. Both systems can be practised, but the traditional one is cardinal numbers only — the counting words. It does not produce ordinals (y pymthegfed, yr ail ar bymtheg, yr unfed ar hugain), and dates need those. Finishing this drill does not equip you to say or read a date; that is a separate piece of the language.

Where the forms come from. The traditional list now runs from 1 to 100. Up to 21, and at the round numbers, it is what Welsh speakers told us directly. In between it follows the rule they and the reference works agree on — a unit, then a (or ar in the twenties), then the score: tri a deugain is 43. Those forms are documented rather than individually checked by a speaker, and we say so here rather than pretending otherwise. Anything with neither a speaker nor a source behind it — 120, and the word for zero — is still skipped by the drill entirely.

What the drill asks you. Not all of it equally. The numbers you need for dates and the time (1–31) and the round scores come up often; the 41–99 compounds come up as recognition practice; the stacked ones (pedwar ar bymtheg ar hugain, 39) are rare on purpose. Welsh speakers told us the system is used unevenly, so drilling it evenly would be practising the wrong half.

Speak Welsh? Please correct us. Everything here was built with Welsh speakers and it still has gaps — forms only one person has vouched for, forms we take from a reference book rather than from anyone's mouth, and wording in the explanations that may be a shade too confident. Telling us a form is right helps as much as telling us it is wrong. The whole site is open source, so corrections, issues and pull requests are all welcome at github.com/stefanwezel/diminumero.

1–10: the building blocks

Memorise these — everything else is built from them:

1 = un
2 = dau
3 = tri
4 = pedwar
5 = pump
6 = chwech
7 = saith
8 = wyth
9 = naw
10 = deg

Two of these shorten before another number word: pump → pum and chwech → chwe (apocope) before deg, cant or mil.

11–19: un deg X

The decimal system uses un deg (“one ten”) plus the digit:

11 = un deg un
12 = un deg dau
13 = un deg tri
14 = un deg pedwar
15 = un deg pump
16 = un deg chwech
17 = un deg saith
18 = un deg wyth
19 = un deg naw

20–99: tens with mutations

Each tens word is the digit + deg, but 2 triggers a soft mutation (d → dd) and 5 and 6 apocopate:

20 = dau ddeg (soft mutation: d → dd)
30 = tri deg
40 = pedwar deg
50 = pum deg (pump → pum)
60 = chwe deg (chwech → chwe)
70 = saith deg
80 = wyth deg
90 = naw deg

Compounds add the unit after a space:

21 = dau ddeg un
47 = pedwar deg saith
99 = naw deg naw

Quick check: 22, 56, 88?

22 dau ddeg dau · 56 pum deg chwech · 88 wyth deg wyth

Hundreds

The word for 100 is cant. Multipliers trigger different mutations:

100 = cant
200 = dau gant (soft mutation: c → g)
300 = tri chant (aspirate mutation: c → ch)
400 = pedwar cant
500 = pum cant
600 = chwe chant (aspirate mutation)
700 = saith cant
800 = wyth cant
900 = naw cant

Combine with tens and units after a space:

134 = cant tri deg pedwar
365 = tri chant chwe deg pump

Thousands & millions

Mil is a feminine noun, so 2–4 use the feminine forms (dwy, tair, pedair) and trigger soft mutation:

1,000 = mil
2,000 = dwy fil
3,000 = tair mil
4,000 = pedair mil
5,000 = pum mil
6,000 = chwe mil
10,000 = deg mil
100,000 = can mil (cant → can before mil)
1,000,000 = miliwn

Larger compounds chain together:

1,234 = mil dau gant tri deg pedwar
5,000,000 = pum miliwn

Common mistakes

Forgetting apocope: it’s pum deg not “pump deg”, and chwe deg not “chwech deg”.
Soft vs. aspirate mutation: dau triggers soft (dau gant), but tri and chwe trigger aspirate (tri chant, chwe chant).
Feminine concord with mil: use dwy/tair/pedair before mil, not dau/tri/pedwar.
Decimal vs. vigesimal: in this quiz, dau ddeg = 20, not ugain. The vigesimal system you may hear in older speech (deugain = 40, hanner cant = 50) isn’t used here.