a quantity that can have different values and can be represented with a word, symbol or pronumeralexpand

The description you provided refers to a "variable". In mathematics and science, a variable is a quantity that can change or vary. It can be represented by a symbol, a letter, or a word.

Here are the steps to understand it:

1. Identify the Variable: In an equation or a problem, identify the quantity that is changing or can have different values. This is your variable.

2. Representation: Choose a symbol, letter, or word to represent this variable. In most cases, letters from the end of the alphabet (like x, y, z) are used.

3. Use in Equations: Now, you can use this representation in equations or formulas. For example, if 'x' is your variable, you can write an equation like 'x + 2 = 5'. Here, 'x' can have different values.

4. Solve: If possible, solve the equation to find the value of the variable. In the above example, you can solve for 'x' to find that 'x = 3'.