Why does my child think 3x + 4 = 7x?
Your child combines terms that can't be combined, such as x and a number.
Why children do it
Adding the numbers they can see is natural, but only like terms combine: x terms with x terms, and plain numbers with plain numbers. 3x + 4 is three x's and four ones, which can't be put together, any more than 3 apples and 4 oranges make 7 apples.
How to help at home
Sort the terms into two piles, x terms and plain numbers. Only terms in the same pile can be added together.
The right way
Simplify: 7x + 9 + 8x + 5
- 7x + 8x + 9 + 5Put the like terms together.
- 15x + 14Add the x terms, then the numbers.
Find out where your child is
A free maths check, in about 15 minutes, shows what your child knows and the mistakes they make. No sign-up.
Start the free checkRelated mistakes
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