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Why Use Letters?
Why Use Letters?
Imagine you're buying apples at a market. You don't know how many you'll buy yet, so instead of writing "cost = 50p Ć ???", you write "cost = 50p Ć n" where n is the number of apples. That's algebra! Letters are placeholders for numbers we don't know yet - they're like empty boxes waiting to be filled.
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Common Mistakes to Avoid
ā x3 + 5
ā 3x + 5
Numbers go before letters
ā xx
ā xĀ²
Use powers for repeated multiplication
ā 1x
ā x
We don't write the coefficient 1
ā 3 Ć x
ā 3x
No multiplication sign needed
ā Confusing xĀ² and 2x
ā xĀ² = xĆx, but 2x = 2Ćx
These are VERY different!
ā Forgetting the sign: term is "7"
ā In 3x ā 7, constant is ā7
The sign belongs to the term
Now try it yourself
Quiz Ā· Question 1 of 13
In the expression 7x, what is the coefficient?
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This topic in real past papers
Every real exam question we've found on algebraic notation, with a full worked answer.