Basic Algebra
Letters stand for numbers. Find the mystery number that makes the equation true.
What is a variable?
In algebra, we use letters like x, y, or n to stand for a number we don't know yet. Our job is to find what number the letter represents. The letter is called a variable.
Think of it like a mystery box: ? + 3 = 7. What number is in the box? It must be 4, because 4 + 3 = 7!
Balance the equation
An equation is like a balance scale: the left side must equal the right side. If you take something away from one side, you must take the same away from the other side to keep it balanced.
Find the value of x:
Try a few more
Each problem gives you a new equation. Find the value of x that makes both sides equal.
Click to try this one:
What is x?
Why does this matter?
Algebra is the language of relationships. When you say "I am 3 years older than my brother", that's algebra: your age = brother's age + 3. Once you can solve for x, you can find any missing number in real life.
Engineers use algebra to build bridges. Scientists use it to predict the weather. Game makers use it to make characters move. You use it every time you ask: "How much more do I need?"