"Η φάρμα έχει σαράντα άλογα."

[mizinamo]

In case you were wondering why σαράντα looks "nothing like" the word for 4, it's short from τεσσαράκοντα, where the relationship to τέσσερα is a lot more obvious.

[nacreousnereid]

How about the root τεταρτο as in "fourth" or "Wednesday," or the root of "Tetris"? Is that short for anything? Or does τεσσαρτο just sound bad in Greek?

[mizinamo]

I don't know for sure.

However, -ττ- and -σσ- sometimes interchanged in Ancient Greek depending on the dialect -- for example, "sea" (θάλασσα in modern Greek) was θάλαττα in Attic Greek. (See e.g. https://en.wikipedia.org/wiki/Thalatta!_Thalatta! )

So I suppose τέσσερις had a form τέττερις in some dialects, and this may be related to the -τ- in τετρα- and τέταρτο.

It may also be related to the fact that "nine" is εννέα (two nus) while "ninth" is ένατο (one nu).

[nacreousnereid]

Interesting!

[an3stis]

The archaic form "fourty" is now considered a misspelling.

[Theo_Matrakas]

Thanks for the info! We have corrected it :D

[D_..]

It's still not marked as a typo though.

[ignac]

Σαράντα looks a bit similar to Russian сорок, but probably there is no etymological relationship between them: https://en.wiktionary.org/wiki/%D1%81%D0%BE%D1%80%D0%BE%D0%BA.
Still this might be helpful for memorizing it.

[Anastasia773993]

That's right. And Russian "sorok" (сорок) doesn't have any relation to the Russian number 4 either.