Full Idea
Why is arithmetic so hard to learn, and why does it seem so easy to us now? For example, subtracting 789 from 26,789.
Gist of Idea
Why is arithmetic hard to learn, but then becomes easy?
Source
Thomas Hofweber (Number Determiners, Numbers, Arithmetic [2005], §4.2)
Book Reference
-: 'Philosophical Review 114' [Phil Review 2005], p.198
A Reaction
His answer that we find thinking about objects very easy, but as children we have to learn with difficulty the conversion of the determiner/adjectival number words, so that we come to think of them as objects.