Pasted

var calculate = document.getElementById("calculate");
calculate.addEventListener("click", showAnswer);
 
var restart = document.getElementById("restart");
restart.addEventListener("click", removeAnswer);
 
function showAnswer() {
  var answer = document.getElementById("show-answer");
  answer.innerHTML = "Hello World";
}
 
function removeAnswer() {
  var answer = document.getElementById("show-answer");
  answer.innerHTML = "";
}