John Gill Commentary Numbers 26:23

"The sons of Issachar after their families: [of] Tola, the family of the Tolaites; of Puvah, the family of the Punites;" — Numbers 26:23 (ASV)

Ver. 23-25. Of the sons of Issachar, after their families

This tribe was numbered next to Judah, because it was under his standard. Two of his sons are a little differently named than they are (Genesis 46:13) instead of Phuvah one is called Pua, and instead of Job another is called here Jashub;

this tribe consisted of four families, and the number of warlike men in it was 64,300; their increase since the last numbering of them is 9900.