Where does “czterokroć” come from?

czterokroć (Polish) comes from Polish cztery, from Proto-Slavic *četỳre, from Proto-Balto-Slavic ketures, from Proto-Indo-European kʷetwóres, from Proto-Indo-European kʷe- — and.

Ancestry of “czterokroć”, step by step

Step	Language	Word	Meaning
1	Polish	cztery	four
2	Proto-Slavic	*četỳre	four
3	Proto-Balto-Slavic	ketures	four
4	Proto-Indo-European	kʷetwóres	four
5	Proto-Indo-European	kʷe-	and

Every word from Proto-Indo-European kʷe- →Every word from Proto-Indo-European kʷetwóres →Every word from Proto-Balto-Slavic ketures →