Board Thread:General Discussion/@comment-46171678-20200726024000/@comment-3544775-20200727181059

There is no official numeration in the manga. The chapters are divided because they came out separately. Additionally a lot of early ones were featured in variety of Jump magazines and were "special" (shorter) chapters and not "main", thus they are referred as "XX.5" and the like.

The series started in Jump SQ, but soon moved to Jump SQ.19. Anything not in SQ.19 is counted as ".5" between the "main" chapters. The series then continued as B2B in SQ.Crown (successor of SQ.19) and later Rise (Crown successor). Anything in Crown/Rise is "main" chapter, anything outside of it Jump SQ, Shonen Jump, Young Jump, etc is "Special" and counted as ".5", ".6", etc chapter.

The numeration on the wiki is consistent, not sure why you think its inconsistent. Although I do see inconsistency after vol4, but that's because you added those numbers yourself.