Numbers 11-99: un deg un

Numbers 11 to 99

Level 2

Modern Welsh numbers work like a calculator: say how many tens, then the units. Tri deg pump is "three tens five" = 35.

How It Works

The tens:

  • 10 deg
  • 20 dau ddeg (deg softens after dau)
  • 30 tri deg
  • 40 pedwar deg
  • 50 pum deg (pump shortens)
  • 60 chwe deg (chwech shortens)
  • 70 saith deg
  • 80 wyth deg
  • 90 naw deg

Adding units. Just add the unit with no "and": un deg un (11), un deg pump (15), dau ddeg un (21), tri deg chwech (36), naw deg naw (99).

When the whole number mutates. After a trigger such as yn, only the first word changes: Dw i'n dri deg oed (I'm thirty), Mae e'n bum deg. See oed for age.

With nouns. A noun straight after a number is singular (see number + singular noun), but with bigger decimal numbers speakers usually say o + a soft-mutated plural: dau ddeg pump o blant. See decimal numbers + o + plural.

Two systems. This decimal system is used in school, maths, prices, phone numbers and most counting. The older system that counts in twenties (un ar ddeg, ugain) is still normal for clock times and common in ages and dates; see traditional numbers un ar ddeg ugain.

Examples (6)

  1. un deg un, un deg dau, un deg tri

    eleven, twelve, thirteen

    One ten one, one ten two, one ten three.

  2. dau ddeg, tri deg, pedwar deg, pum deg

    twenty, thirty, forty, fifty

    Deg softens after dau; pump shortens to pum.

  3. chwe deg, saith deg, wyth deg, naw deg

    sixty, seventy, eighty, ninety

    Chwech shortens to chwe.

  4. Mae dau ddeg pump o blant yn y dosbarth.

    There are twenty-five children in the class.

    With a bigger number, o + a soft-mutated plural: plant → blant.

  5. Mae Taid yn wyth deg saith oed.

    Grandad is eighty-seven.

    Taid is the Northern word for grandad; the South says tad-cu.

  6. Mae'r bws rhif chwe deg yn mynd i'r dref.

    The number sixty bus goes to town.

Common Mistakes

  • Forgetting to soften deg after dau.

    dau deg
    dau ddeg

    Dau causes soft mutation, so twenty is dau ddeg.

  • Using the full form pump before deg.

    pump deg
    pum deg

    Before deg, pump shortens to pum and chwech to chwe: pum deg, chwe deg.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

Numbers 11-99: un deg unLevel 2Numbers 11 to 99

Learn This First

Decimal tens build on dau and its soft mutation.

Words in This Pattern

pumchweun deg undau ddegdau ddeg pumptri degpum degchwe degnaw deg naw