The more ancient vernacular numerals are the native numbers of Hokkien that trace back to Hokkien's origins itself, which is a Coastal Min language that spread southwest across the coast of Fujian from around the Min River.
[1] Meanwhile, the literary system came from Tang-era Classical Chinese/Middle Chinese that was loaned in for formal reading use during medieval times[2] (e.g. Tang, Min, Southern Tang, Song dynasty times), similar to the Sino-Xenic pronunciations in Japanese, Okinawan, Korean, Jeju, Vietnamese, etc, but within the Sinitic family to the Min group.
Literary and colloquial systems are not totally mutually independent; they are sometimes mixed used.
From now on, see Chinese numerals For cardinal numbers usage, the colloquial system is usually used.
It means the first seven days after a person died, which is a Hokkien cultural noun that should usually be avoided.