text: //exercise 007
  function somar() {
      var txtn1 = document.getElementById('txtn1');
      var txtn2 = document.getElementById('txtn2');
      var num1 = Number.parseFloat(txtn1.value);
      var num2 = Number.parseFloat(txtn2.value);
      s = num1 + num2;
      result.innerHTML = `Resultado: ${num1} + ${num2} = <strong>${s}</strong>`;
  }
  