Step by step
The question
Question: write with math signs: 10 less than double a number.
10 less than double a number
1 Change words to math
2 Put it in order
Less than turns the order around.
We start with double a number, then take away 10.
So we get 2n − 10.
= 2n − 10
Careful: 2n − 10 is not the same as 10 − 2n.
The order matters when we take away.
Careful: 2n − 10, not 10 − 2n
3 Check
Let's check with a number.
Say the number is 10.
10 less than double 10 is 10.
10 less than double 10 is 10
And 2(10) − 10 is 10 too.
So 2n − 10 is right!
2(10) − 10 = 10
Let's look back.
First: change words to math.
Then: put it in order.
Last: check.
Answer
= 2n − 10