In math, a constant is a special value that doesn’t change. The symbol is often used in an expression to indicate a generic unchanging value. There are also some math constants that mathematicians have given their own symbol

mathematicians have

a significant value that mathematicians have assigned a symbol representation.

The circle constant τ (tau) is a geometric constant approximately equal to 6.283. The numeric value is defined as the length of any circle's circumference divided by the length of its radius.

The greek letter π (pi) is a geometric constant approximately equal to 3.1416. Its value is equal to the length of any circle's circumference divided by its diameter.

Euler's number is a naturally occurring number related to exponential growth and exponential decay. It is also shorthand for the exponential function.

The golden ratio is a number represented by the greek letter ϕ (phi). The value of ϕ is approximately 1.618 and is a naturally occurring number in nature.

The letter "i" is used in mathematics to represent the square root of negative one. The letter is also used to denote the complex part of a complex number.