1. The problem is to understand the difference between the variables $5$ and $s$. 2. In algebra, $5$ is a constant number, while $s$ is a variable that can represent any number. 3. Variables like $s$ are used to represent unknown or changing values in equations. 4. For example, if you have the expression $s + 3$, it means you add 3 to whatever value $s$ represents. 5. If $s = 5$, then $s + 3 = 5 + 3 = 8$. 6. So, $5$ is a fixed number, and $s$ is a symbol that can take different values depending on the problem.