The document defines and describes several types of numbers:
Natural numbers (N) are the counting numbers 1, 2, 3, etc. with no greatest number. Whole numbers (W) include 0. Integers (Z) include both positive and negative numbers. Rational numbers (Q) are numbers that can be written as p/q where p and q are integers. Irrational numbers cannot be written as p/q. Real numbers (R) include all rational and irrational numbers.
The number line represents all real numbers as unique points. Ancient Greek mathematicians like Pythagoras, Cantor and Dedekind studied properties of rational and irrational numbers and their representation on the number line. Decimal expans