What are expressions? An introduction.

A mathematical expression consists of numbers, letters, and operations - but it cannot have an equal sign. We look at some examples, and then delve into this question:

What do we do with expressions?

One thing we do is, we can use expressions to build EQUATIONS, because an equation always consists of two expressions separated by an equals sign.

But in this lesson we focus on another common task: EVALUATING expressions for specific values of the variable(s).

This lesson is intended for 6th grade math and onward. The 2nd part of the lesson will help you write expressions from words, and it is found here:

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Can a number by itself be an expression?

For example:

2?