text: function subtract() {
      let firstNumber = Number(document.getElementById("firstNumber").value);
      let secondNumber = Number(document.getElementById("secondNumber").value);
      let resultElement = document.getElementById("result");
  
      //let biggerN = Math.max(firstNumber, secondNumber);
      //let smallerN = Math.min(firstNumber, secondNumber);
      let result = firstNumber - secondNumber;
      resultElement.textContent = result;
  }