Charles Ellicott Commentary Numbers 26:37

"These are the families of the sons of Ephraim according to those that were numbered of them, thirty and two thousand and five hundred. These are the sons of Joseph after their families." — Numbers 26:37 (ASV)

Thirty and two thousand and five hundred.— This shows a decrease of 8,000. Jacob foretold that Ephraim should be greater than Manasseh (Genesis 48:19). At the former census, the number of the Ephraimites was considerably greater than that of the Manassites (Numbers 1:33; Numbers 1:35), and Ephraim was made a standard-bearer (Numbers 2:18). At the present census, however, the number of the Manassites exceeded that of the Ephraimites by 20,200; and yet, in the face of the great increase of Manasseh and the diminution of Ephraim, Moses renewed and confirmed Jacob’s prediction concerning the ultimate superiority of Ephraim, and while ascribing only “thousands” to Manasseh, he speaks of the “ten thousands of Ephraim” (Deuteronomy 33:17).