Numbers 1:20 in the 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;
Context
19 As the LORD commanded Moses, so he counted them in the wilderness of Sinai.
20 The children of Reuben, Israel’s firstborn, their generations, by their families, by their fathers’ houses, according to the number of the names, one by one, every male from twenty years old and upward, all who were able to go out to war:
21 those who were counted of them, of the tribe of Reuben, were forty-six thousand five hundred.