King James Version
And the children of Reuben, Israel's eldest son, by their generations, after their families, by the house of their fathers, according to the number of the names, by their polls, every male from twenty years old and upward, all that were able to go forth to war;English Standard Version
The people of Reuben, Israel's firstborn, their generations, by their clans, by their fathers' houses, according to the number of names, head by head, every male from twenty years old and upward, all who were able to go to war:New International Version
From the descendants of Reuben the firstborn son of Israel: All the men twenty years old or more who were able to serve in the army were listed by name, one by one, according to the records of their clans and families.