The note
How schools teach it now
In Year 6 a letter stands for an unknown number ('missing number problems'). Schools use the idea of a balance (do the same to both sides) and inverse operations. Children write 3n, not 3 × n or n3.
5-minute kitchen-table activity
Put some coins in an envelope. Place the envelope and 3 loose coins on one side of the table and 10 coins on the other: 'They're worth the same. How many coins in the envelope?' (7.) Then try two envelopes.
Worked example
Solve 3n + 5 = 26.
- Take 5 from both sides: 3n = 21.
- Divide both sides by 3: n = 7.
- Check: 3 × 7 + 5 = 26.
Answer: n = 7
Common mistakes to watch for
- Reading 3n as 3 + n, or as a number in the thirties.
- Undoing the steps in the wrong order (dividing before subtracting).
- Not checking the answer by putting it back in.
Encouragement
- Try saying
- “Whatever you do to one side, do to the other.”
- Rather than
- “Algebra is secondary-school stuff, don't worry.”