Question

A letter that represents an unknown number is

Answer 1

Hey there! Hello!

I believe what this question (more of a statement) is asking is to identify what a letter that represents an unknown number is called. Most of the time, i refer to it as just a variable, or an unknown variable. It can also be referred to as just an unknown value. 

Feel free to ask me any additional questions if you have any! :-)

Answer 2

The variable that's what it is called.. it could be represented with any letter but x most of the time