In Year 7, it's really important to understand variables and constants when we learn about algebra.

• Variables are like empty boxes that can hold numbers. They usually have letters like $x$, $y$, or $z$. For example, in the expression $2x + 3$, the letter $x$ is the variable. This means it can change depending on the situation.

• Constants, on the other hand, are numbers that stay the same no matter what. In the expression $2x + 3$, the number $3$ is a constant because it doesn’t change.

When you combine them, like in $3x + 5$, you create an algebraic expression. This expression can represent different answers depending on the variable.

It’s all about mixing and matching!