stateless. A stateless server is one which treats each request as an independent transaction, unrelated to any previous request. This simplifies the server design because it does not need to allocate storage to deal with conversations in progress or worry about freeing it if a client dies in mid-transaction.
An expression in a programming language is a combination of one or more explicit values, constants, variables, operators, and functions that the programming language interprets (according to its particular rules of precedence and of association) and computes to produce (to return, in a stateful environment) another value.
Both use numbers and variables; however it is all based on the arrangement. So let's take look at both to determine their use and relationship. An expression is a combination of numbers, variables, and symbols to be calculated. An equation contains expressions that are separated by an equals sign. A further look at the mathematical expression can be explained with numbers and variables such as: 7x + y - 4.