function solve () {
  let selectMenu = document.getElementById('selectMenuTo')
  //   let newOption = document.createElement('option')
  //   newOption.textContent = 'Hexadecimal'
  //   selectMenu[0].textContent = 'Binary'
  //   selectMenu.append(newOption)
  let currentNumber = document.getElementsByTagName('input')
  let resultId = document.getElementById('result')
  let button = document.getElementsByTagName('button')

  // my code***********************************************
  let binaryOption = document.createElement('option')
  binaryOption.setAttribute('value', 'binary')
  binaryOption.textContent = 'Binary'

  let hexadecimalOption = document.createElement('option')
  hexadecimalOption.setAttribute('value', 'hexadecimal')
  hexadecimalOption.textContent = 'Hexadecimal'

  selectMenu.appendChild(binaryOption)
  selectMenu.appendChild(hexadecimalOption)
  // my code***********************************************

  button[0].addEventListener('click', function () {
    let result = 0
    let number = currentNumber[0].value
    let selectedOption =
      selectMenu.options[selectMenu.selectedIndex].textContent
    if (selectedOption === 'Binary') {
      result = (+number).toString(2)
    } else if (selectedOption === 'Hexadecimal') {
      result = (+number).toString(16).toUpperCase()
    }
    console.log(result)
    currentNumber[0].value = ''
    resultId.value = result
  })
}