- Mathematics : The study of quantities, structures, their relations, and changes thereof.
- Prime number : A number that can be evenly divided by exactly two positive whole numbers, namely one and itself.
- Whole number : Add brief definition or description
- Rational number : A number that can be expressed as a ratio of two integers.
- Irrational number : A real number that cannot be expressed as a fraction, m / n, in which m and n are integers.
- Real number : A limit of the Cauchy sequence of rational numbers.
- Complex number : Numbers of the form a+bi, where a and b are real numbers and i denotes a number satisfying .
- P-adic number : Add brief definition or description
- Parts-per notation : Notation used in science and engineering, to denote dimensionless proportionalities in measured quantities such as proportions at the parts-per-million (ppm), parts-per-billion (ppb), and parts-per-trillion (ppt) level.