I thought that "chwech" becomes "chwe" before a noun. Is that not true here because it is a compound number or for another reason?
Chwe is just a shortened version of the word. I think it's mainly used in north Wales
Yes, chwech becomes chwe before a noun and causes aspirate mutation. Pump also becomes pum before a noun.
I was taught to say numbers like this in school (North Wales), but I think there are different ways in saying numbers above ten, for example I know that "un deg un" and "unarddeg" both mean eleven. Out of interest, what would the alternate of "pedwar deg chwech" be?
I learned that too but only for the teens: unarddeg, dauarddeg, triarddeg, ... nawarddeg. Pedwararchwedeg? I'm not sure if there'd be a mutation in there on the chwedeg tho. I haven't got to that yet.
un ar ddeg, deuddeg, tri ar ddeg, pedwar ar ddeg, pymtheg, un ar bymtheg, dau ar bymtheg, deunaw, pedwar ar bymtheg :)
18 is "twonines", not "eight-on-ten" or "three-on-fifteen".
46 would be "chwech a deugain" (six and two-twenties).
And 64 would be "pedwar a thrigain" (four and three-twenties, with aspirate mutation on "trigain").
I know it translates to 46, I'm just confused as to why you're saying "pedwar deg chwech" is incorrect. Unless I'm just misunderstanding!
It's not incorrect. One of the correct solutions is 40 6, which is four hundred and six, albeit with odd spacing.
Oh! I see what you mean now, my apologies. Yeah that definitely doesn't make sense.
i'm guessing that if you were listing numbers then you could say: pedwar deg, chwech = forty, six.