It's about time you start telling us what YOU THINK the answers to these questions are. You can often find out by conducting a search (http://www.google.com) or looking up terms in a good online dictionary, such as http://www.answers.com .
The math term you are referring to is "variable." In mathematics, a variable is a symbol that represents an unknown number or quantity. It is often denoted by a letter, such as x, y, or z. Variables are used to represent and solve equations and can take on different values to make the equation true. By assigning values to variables, you can find solutions and determine relationships between different quantities in mathematical expressions.
