When I first started learning algebra in 7th grade, I found the ideas of variables and constants a bit tricky. But once I understood them, everything started to make sense. Here’s how I figured out the difference between the two:

1. Understanding the Basics

• Constants are numbers that stay the same. For example, in the math sentence $5 + 3$, the numbers $5$ and $3$ are constants. Think of them like friends who always stick to their plans. You know exactly what they are.

• Variables are letters that stand for numbers we don’t know yet and can change. They often look like $x$, $y$, or $z$. So in the sentence $2x + 4$, the $x$ is the variable that can be different in each situation. You can think of variables as surprise guests who can show up in different ways, depending on what we’re talking about.

2. Identifying Them in Expressions

To tell variables and constants apart in a math sentence, here are some easy tips:

• Look for Letters vs. Numbers: If you see a letter, it’s a variable. If you just see a number, it’s a constant. For example, in the expression $3a + 7$, $a$ is the variable, while $3$ and $7$ are constants.

• Context Matters: Sometimes, the same letter can mean different things in different problems. For example, $x$ might mean the number of apples in one problem but the number of students in another.

3. Using Examples

Try writing down some math sentences and labeling their parts. For example:

• In $4y + 2$, $4$ and $2$ are constants, and $y$ is the variable.
• In $x^2 + 5x - 10$, the $-10$ is a constant, while $x$ is the variable.

By practicing with different math sentences, I got a lot better at spotting variables and constants!