New Textbooks for the "New" Mathematics
Feynman, Richard P. (1965)
https://calteches.library.caltech.edu/2362/

'... In a first-grade book (a primer, in fact) I find a sentence of the type: "Find out if the set of the lollypops is equal in number to the set of girls" - whereas what is meant is: "Find out if there are just enough lollypops for the girls." ...'