What does eslint want?

Question

Linter

Hello!
So I took it upon myself to check my mini tutorial code with a linter, and there is such an error
12:17 warning No magic number: 2 no-magic-numbers
12:41 warning No magic number: 2 no-magic-numbers
What can this mean? I so understood from the documentation that it is connected with variables. In these lines, my variables appear in the expression.
Who faced? Or maybe you just know English better, please help me figure it out.
Thank you for your responses.
Here is my code

let a1,a2,b1,b2,c1,c2;

 a1 = +prompt('enter first A point');
 a2 = +prompt('enter second A point');

 b1 = +prompt('enter first B point');
 b2 = +prompt('enter second B point');

 c1 = +prompt('enter first C point');
 c2 = +prompt('enter second C point');

if ((a1 + b1) / 2 === c1 && (a2 + b2) / 2 === c2) {
    console.log('true')
} console.log('false');