text: class Hex {
    constructor(number) {
      this.value = number;
    }
  
    valueOf() {
      return this.value;
    }
  
    toString() {
      return "0x" + (this.value.toString(16).toUpperCase());
    }
  
    plus(secondNewObj) { // kude pishe obekt we?
      let newObj = new Hex(this.value + secondNewObj.valueOf());
      return newObj;
    }
  
    minus(secondNewObj) { // kude pishe obekt we?
      let newObj = new Hex(this.value - secondNewObj.valueOf());
      return newObj;
    }
  
    parse(kur) { 
      // ???
    }
  
  }
  
  // let FF = new Hex(255);
  // let actual = FF.toString();
  // let expected = "0xFF";
  // console.log(actual);
  // console.log(expected);
  // console.log(FF.valueOf() + 1); 
  
  let a = new Hex(10);
  let b = new Hex(5);
  let act = a.plus(b).toString();
  let exp = "0xF";