Woa, this have 5 volumes already, Naruto with 5 volumes had 45 chapters, mangas nowadays are very thin hm.
let me do some math, a Naruto chapter had 20 pages, Shoukan sareta Kenja have 40 pages.
So, it is.
1 Naruto volume had 10 chapters:
20x10 = 200 pages
1 Shoukan sareta Kenja volume have 4...