Oh I think so too But I was playing devil’s advocate as I’m often critical of the fundamental irreality of math and it ‘clicked in’ that quantity is category.
So, to disentangle quantity, I think it might help to generalize to “category” and ask:
Are categories real and/or valid?
I suppose it’s possible for all categories to ultimately resolve to [SET OF 1 MEMBER], which might consequently dissolve mathematics.
But… that’s on a flat plane. “all things being equal”.
Does a “thing” have qualities?
Can those qualities go into categories?
If there is more than one member in a [[set of] ‘category’], you now have quantity.
Round thing In this location at this time.
Round thing in this location at this time.
Two round things.