3.3 Numbers

This chapter describes Scheme’s model for numbers. It is important to distinguish between the mathematical numbers, the Scheme objects that attempt to model them, the machine representations used to implement the numbers, and notations used to write numbers.

In this report, the term number refers to a mathematical number, and the term number object refers to a Scheme object representing a number. This report uses the types complex, real, rational, and integer to refer to both mathematical numbers and number objects. The fixnum and flonum types refer to special subsets of the number objects, as determined by common machine representations, as explained below.