text: document.getElementById("btn0").addEventListener("click", function() {
    document.getElementById("res").insertAdjacentHTML("beforeend", "0");
  });
  
  document.getElementById("btn1").addEventListener("click", function() {
    document.getElementById("res").insertAdjacentHTML("beforeend", "1");
  });
  
  function operatorAction(eve) {
    let btn = eve.target;
    // Add the inner html for the operator buttons into the results field
    document.getElementById("res").insertAdjacentHTML("beforeend", btn.innerHTML);
  }
  
  document.getElementById("btnSum").onclick = operatorAction;
  document.getElementById("btnMul").onclick = operatorAction;
  document.getElementById("btnDiv").onclick = operatorAction;
  document.getElementById("btnSub").onclick = operatorAction;
  
  document.getElementById("btnClr").onclick = function() {
    document.getElementById("res").innerHTML = "";
  };
  