Solving One-Step Equations

What is an Equation?

An equation is a statement that two expressions are equal.

Example: $x + 5 = 12$

Inverse Operations

Operations that "undo" each other:

• Addition ↔ Subtraction
• Multiplication ↔ Division

Solving Addition Equations

Undo addition with subtraction

$x + 5 = 12$ $x + 5 - 5 = 12 - 5$ $x = 7$

Solving Subtraction Equations

Undo subtraction with addition

$x - 3 = 10$ $x - 3 + 3 = 10 + 3$ $x = 13$

Solving Multiplication Equations

Undo multiplication with division

$4x = 20$ $\frac{4x}{4} = \frac{20}{4}$ $x = 5$

Solving Division Equations

Undo division with multiplication

$\frac{x}{3} = 7$ $3 \times \frac{x}{3} = 7 \times 3$ $x = 21$

Golden Rule

Whatever you do to one side, do to the other side!

This keeps the equation balanced.

Checking Solutions

Substitute your answer back into the original equation.

If both sides are equal, you're correct!