Edit : I do remember the half a dozen I use or might really need, and already feel like an outlier. ( And as pointed in another comment, they're already 11 digits each. Not that much of a difference. )
Yup, all the ones I knew as a kid in the 80s and early 90s, and haven't used for 2 decades.
Children do, or should. Even very young children should be taught until they have memorized their own phone number.
And even older children might not have phone yet, but still need to be able to call home.