In the beginning, people thought of computers as number crunchers. And
indeed, computers are very good at working with numbers. Since teachers
start their first-graders on computing with numbers, we start with numbers,
too. Once we know how computers deal with numbers, we can develop simple
programs in no time; we just translate common-sense into our programming
notation. Still, even developing such simple programs requires discipline,
and so we introduce the outline of the most fundamental design recipe and
the basic programming guideline at the end of this section.