class Hex{
    constructor(value){
        this.value = value
    }

    valueOf(){
        return this.value;
    }

    toString(){
        let hex = this.value.toString(16).toUpperCase();
        let result = `0x${hex}`;
        return result;
    }

    plus(num)
    {
        let result = this.value + num;
        return `0x${result.toString(16).toUpperCase()}`;
        
    }

    minus(num)
    {
        let result = this.value - num;
        return `0x${result.toString(16).toUpperCase()}`;
    }

    parse(num)
    {
        return parseInt(num, 16);
    }
}

let FF = new Hex(255);
console.log(FF.toString());
FF.valueOf() + 1 == 256;
let a = new Hex(10);
let b = new Hex(5);
console.log(a.plus(b).toString());
console.log(a.plus(b).toString()==='0xF');