The fastest and simplest way to teach the principles of programming and computing is to teach the design and the evaluation of functional programs.

Our introduction to functional program design consists of four parts:

1. from information to data and the basic design principles

2. generative recursion aka divide-and-conquer recursion

3. accumulator-style programming

4. functions as first-class values

The evaluation of a functional program proceeds according to rules that are well-known from Algebra I: the substitution of equals for equals and the evaluation of functions for certain arguments. To accomodate basic data, like numbers and truth values, we also need the laws for basic arithmetic operations. To accommodate compound forms of data (which combine several pieces of information into a single datum), we also need to introduce projection laws.