Expression does not have an = sign

9 − 8 is an expression

2x + 3 is an expression

3x − 9 is an expression

4x = 10 is not an expression

4x = 10 has an = Sign

So, it is not an expression

It is an equation

Here,

9 − 8 is an expression

But it does not have a variable

So, it is an expression without variables

But here,

we will study expressions with variables

Let learn how expressions are formed

We can also

Form expressions from statements