A Constant is a fixed number, rather than a variable number.
In the equation v = 10t + 15
The numbers 10 and 15 are constants. v and t can be given
various values – they are variables.
constants are always definable numbers and are almost always
also computable numbers (Chaitin's constant being a significant
exception). However, computable constants need not be easily
computed; the De Bruijn-Newman constant, for example, has
no known digits of its decimal expansion.