C. F. Keil and Franz Delitzsch on 1 Chronicles 4:27

1Ch 4:27

Shimei had sixteen sons and six daughters, by whom he became the father of a numerous race. “His brothers,” i.e., the other Simeonites, on the contrary, had not many sons. Hence it happens that they made not their whole race, i.e., the whole race of the Simeonites, numerous unto the sons of Judah, i.e., that the Simeonites were not so numerous as the descendants of Judah. This account is corroborated by the statement made at the numberings of the people under Moses; see on Num 1-4 (1:2, S. 192).