Chapter 2. Numbers

Numbers are as fundamental to computing as breath is to human life. Even programs that have nothing to do with math need to count the items in a data structure, display average running times, or use numbers as a source of randomness. Ruby makes it easy to represent numbers, letting you breathe easy and tackle the harder problems of programming.

An issue that comes up when you're programming with numbers is that there are several different implementations of "number," optimized for different purposes: 32bit integers, floating-point numbers, and so on. Ruby tries to hide these details from you, but it's important to know about them because they often manifest as mysteriously incorrect calculations.^[1]

^[1] See, for instance, the Discussion section of Recipe 2.11, where it's revealed that Matrix#inverse doesn't work correctly on a matrix full of integers. This is because Matrix#inverse uses division, and integer division works differently from floating-point division.