Answer:
x+15
Explanation:
Since it says "than a number"
What number is it?
We don't know.
We will say thats a variable.
What variable?
Well it really can be anything. ONLY LETTERS
Lets do a x
Now the problem changed.
Fifteen more than x is written as...?
It says "more"
You use plus.
Now the problem changed.
Since is written as... is your answer so yeah
15+x is the problem.
There you go the answer!
People writes the variable first so:
x+15
The answer is x+15