en_tn/1ch/07/02.md

heads of their fathers' houses

The words "father's houses" refers to extended families, people related to each other who usually lived in different houses, what the UDB calls "clans."

They numbered 22,600

"They numbered twenty-two thousand six hundred" or "There were 22,600 men" (See: rc://en/ta/man/translate/translate-numbers)

in the days of David

"during David's life" or "while David was alive"