And I in turn can only venture a guess that you have entirely forgotten the brain-liquefying tedium of modern mathematics education, as shown by the fact that you immediately revert to actually interesting patterns that a properly-educated mathematician might think about.

The dollars-and-cents addition problem mapped onto the "fun" toy store narrative is not mathematically interesting until assigned the type of analytical firepower outlined in OP's blog post. It is a deliberately obtuse trick question posed as a learning tool; children labelled "gifted" will figure it out and feel the dull satisfaction of killing another "problem", and those without that benefit will simply experience more fear and boredom.