Why does my child think 3x is 35 when x = 5?
Your child puts a number next to the value of a letter instead of multiplying, such as 3x with x = 5 as 35.
Why children do it
In algebra, a number written next to a letter means multiply: 3x is 3 × x. Children who put 5 in place of x and write the digits side by side are reading it like a number, 3 then 5. When x = 5, 3x is 15.
How to help at home
Ask what 3x means: 3 lots of x, so 3 × 5, not 35.
The right way
When x = 7, work out: 5x + 1
- 5 × 7 + 1Put 7 in place of x.
- 35 + 1Multiply first.
- 36Then add.
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