ment.getElementById("num2").value;

          document.getElementById("operationMenu").innerHTML =
            "<h2>Choose the operation:</h2> 1. Addition<br/> 6. Quit";

          let operation = parseInt(prompt("Enter choice[1-6]:"));

          let result = null;
          switch (operation) {
            case 1:
              result = num1 + num2;
              break;
            case 2:
              result = num1 - num2;
              break;
            case 3:
              result = n