How we cite our quotes: (Paragraph)
Quote #1
[…] and therefore, whoever could find out a fair, cheap, and easy method of making these children sound and useful members of the commonwealth would deserve so well of the public as to have his statue set up for a preserver of the nation. (2)
Swift is mocking the British approach to public policy, which emphasizes economy first. Absolutely everything has to serve a purpose.
Quote #2
As to my own part, having turned my thoughts for many years upon this imports subject and maturely weighted the several schemes of other projectors, I have always found them grossly mistaken in their computations. (4)
This is the cue for the narrator to start throwing out wild estimates of the number of people in Ireland.
Quote #3
The question therefore is how this number shall be reared and provided for, which, as I have already said, under the present state of affairs is utterly impossible by the methods hitherto proposed. (7)
So far, the narrator hasn't actually stated which methods have failed. There's a lot of political posturing going on, which Swift knows is essential for any kind of political tract—satirical or not.