An equation is a balance. The left side equals the right side, and your job is to find the value of the variable that keeps them equal. Solving means getting the variable alone on one side, like x = a number.

The golden rule

Whatever you do to one side, you must do to the other. This keeps the balance even. To undo an operation, use its opposite: addition undoes subtraction, and multiplication undoes division.

• If a number is added, subtract it from both sides.
• If a number is subtracted, add it to both sides.
• If the variable is multiplied by a number, divide both sides by that number.

The plan

Peel away the numbers around the variable in reverse order. Undo any addition or subtraction first, then undo the multiplication or division last.

Always check your answer by putting it back into the original equation. If both sides come out equal, you solved it right.