What is algebra?

Algebra is all about missing values or numbers.

If you have solved a missing box problem, you have already solved an algebra equation.

Rather than drawing missing boxes or writing the words “missing number”, mathematicians use a letter of the alphabet.

The most commonly used letters are 𝑥 and 𝑦.

Activity: What is algebra?

Complete this interactive activity to better understand algebra. Then put your knowledge to the test.

Sometimes you can solve a problem just by using your knowledge of how addition and subtraction, or multiplication and division, are connected.

But algebra can also be solved by balancing out an equation, like a set of scales.

To keep things balanced, whatever you do to one side, you do to the other side as well.

Once you have just the missing number on one side, then you have found the answer.

Let's look at a problem.

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Any missing number box equation is a form of algebra. Algebra uses letters of the alphabet instead of missing number boxes. The most commonly used letters are 𝑥 and 𝑦.
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You can think of an equation like a set of scales. Both sides of the equals sign must have the same value to be balanced.
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To get 𝑦 on its own you have to subtract 153 from the right side. But to keep the equation balanced, you must do the same to the left side.
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Now, this leaves 𝑦 on it's own. So 𝑦 is 26.
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You can always check your answer, by putting the value back into the original equation.