Why is a-variable-name not valid?

Question

I want to name a variable. So I named it with the above name. But it gives an error message. Why?

Answer 1

Variable names can only have letters, numbers, and underscores. Dashes aren't valid characters.

Answer 2

Please write a more detailed question! so that people can understand and answer you! Hope for understanding
@Sololearn

Answer 3

What tamra said. Right now it looks like you're subtracting "variable" from "a"!