$\"\"$

An equation contains an equal sign and an expression does not.

An equation is made up of two expressions and an equal sign.

For example $\"\"$ and $\"\"$ are expressions and $\"\"$ is an equation.

$\"\"$

An equation contains an equal sign and an expression does not.An equation is made up of two expressions and an equal sign.

$\"\"$ and $\"\"$ are expressions and $\"\"$ is an equation.