Unwrapping the Gift.
Finding the value of a variable by performing the inverse (opposite) operation.
The word 'Algebra' comes from 'Al-Jabr', meaning 'The Reunion of Broken Parts'.
Do the Opposite to BOTH sides.
Plain English: The variable x is annoying. It wants to be alone. If a number is clinging to it, you have to force it away. If the number is Adding, you Subtract. If it is Multiplying, you Divide.
Real-world example: Budgeting. 'I have $50 total, I spent $20, what did I start with?' (x - 20 = 50).
Not doing it to both sides. Equations are a balance scale. If you take weight off the left, you MUST take it off the right or it tips over.