What does Numbers 1:20 mean?

And the children of Reuben, Israel’s first-born, their generations, by their families, by their fathers’ houses, 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;

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;

And the children of Reuben, Israel’s first-born, their generations, by their families, by their fathers’ houses, 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;

The generations of the sons of Reuben, the oldest son of Israel, were numbered by their families and their fathers' houses, every male of twenty years old and over, who was able to go to war;

And the sons of Reuben, Israel's first-born--their births, by their families, by the house of their fathers, in the number of names, by their polls, every male from a son of twenty years and upward, every one going out to the host--

Of Ruben the eldest son of Israel, by their generations and families and houses and names of every head, all that were of the male sex, from twenty years old and upward, that were able to go forth to war,

And the sons of Reuben, Israel's eldest son, their generations, after their families, according to their fathers' houses, by the number of the names, according to their polls, every male from twenty years old and upward, all that went forth to military service: