The study of coins, tokens, medals and paper money / The study of coins / The collecting of coins, tokens, medals and paper money / The collecting of coins

plural of rational number

(mathematics) The set of numbers that can be expressed as a ratio of integers, often denoted with the bold letter Q, or the blackboard bold letter ℚ.

plural of real number

(mathematics) The smallest set containing all limits of convergent sequences of rational numbers.

(complex analysis) A number of the form a + bi, where a and b are real numbers and i denotes the imaginary unit

Used other than figuratively or idiomatically: see random, number. / A number allotted randomly using suitable generator (electronic machine or as simple "generator" as die).

(number theory) An abundant number.

(number theory) A deficient number.

(number theory) A number that is greater than the sum of all of its divisors except itself.