The Little X series;

[1] The Little Schemer: https://mitpress.mit.edu/9780262560993/the-little-schemer/

[2] The Little Prover: https://mitpress.mit.edu/9780262527958/the-little-prover/

[3] The Little Typer: https://mitpress.mit.edu/9780262536431/the-little-typer/

[4] The Little Learner: https://mitpress.mit.edu/9780262546379/the-little-learner/

Note that [1] also has companion volumes: The Seasoned Schemer [1a] and The Reasoned Schemer [1b]

[1a] https://mitpress.mit.edu/9780262561006/the-seasoned-schemer/

[1b] https://mitpress.mit.edu/9780262535519/the-reasoned-schemer/