i want it so i can add randNumber to the existing number in playerOneNum. this is my code until now

const rollBtn = document.getElementsByClassName('btn--new')[0];

let playerOneNum = document.getElementById('current--0');

console.log(playerOneNum.textContent)

rollBtn.addEventListener('click', function(){
    let randNumber = Math.floor(math.random() * 7)
    let outcome = playerOneNum.textContent + randNumber.textContent;

});