Definition that contains real number
- imaginary (mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1
- irrational a real number that cannot be expressed as a rational number
- interval a set containing all points (or all real numbers) between two given endpoints
- positional representation system a numeration system in which a real number is represented by an ordered set of characters where the value of a character depends on its position
- metric space a set of points such that for every pair of points there is a nonnegative real number called their distance that is symmetric and satisfies the triangle inequality
- complex number (mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1
- indefinite integral the set of functions F(x) + C, where C is any real number, such that F(x) is the integral of f(x)
- numerical value a real number regardless of its sign
- real matrix a matrix whose elements are all real numbers
- complex quantity (mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1