Algebra and Equations
Algebra uses letters to represent unknown numbers. Solving simple equations means finding the value of the unknown that makes the equation true.
What You Need to Know
Key Concept Diagram
A variable (e.g. x or n) represents an unknown number in an equation
To solve x + 5 = 12, subtract 5 from both sides: x = 7
To solve 3n = 18, divide both sides by 3: n = 6
Check your answer by substituting back into the original equation
Key Vocabulary
Variable
A letter used to represent an unknown number, e.g. x or n
Equation
A mathematical statement showing two expressions are equal, using an = sign
Solve
To find the value of the unknown that makes the equation true
Inverse operation
The operation that undoes another: subtraction undoes addition, division undoes multiplication
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
Solve: x + 8 = 15
Question 2
Solve: 4n = 28
Question 3
Which equation means "a number multiplied by 6 equals 42"?
Key Concepts Summary
- ●A variable (e.g. x or n) represents an unknown number in an equation
- ●To solve x + 5 = 12, subtract 5 from both sides: x = 7
- ●To solve 3n = 18, divide both sides by 3: n = 6
- ●Check your answer by substituting back into the original equation