The note
How schools teach it now
Primary schools teach inverse operations and the balance idea. Letters on both sides is usually Year 7 work, but some 11+ papers include it: take the same amount off both sides until the letter is on its own.
5-minute kitchen-table activity
Play 'think of a number': 'I think of a number, double it and add 7. I get 19. What was my number?' Your child undoes each step: 19 − 7 = 12, then 12 ÷ 2 = 6. Take turns.
Worked example
Solve 5x + 3 = 2x + 18.
- Take 2x from both sides: 3x + 3 = 18.
- Take 3 from both sides: 3x = 15.
- Divide by 3: x = 5. Check: 5 × 5 + 3 = 28 and 2 × 5 + 18 = 28.
Answer: x = 5
Common mistakes to watch for
- Changing only one side of the equation.
- Stopping at 3x = 15 instead of finding x.
- Mixing up the inverse: undoing + 3 by adding 3.
Encouragement
- Try saying
- “Let's keep it balanced, one step at a time.”
- Rather than
- “This is too advanced for you.”