Buenos días, quisiera saber si realice bien la declaración e inicialización de variables segun la siguiente pagina : https://developer.mozilla.org/es/docs/Learn/JavaScript/First_steps/Test_your_skills:_variables.
Lo realice en la plataforma Codepen, en el siguiente enlace: https://codepen.io/jairbaum/pen/abyGQWQ
Hi @jairobautista0907 and welcome to the community 
Congratulation on you first tasks! You show that you understood the topic.
If you plan to post more tasks I strongly recommend using one CodePen per task and putting the whole code into CodePen (separated into HTML, CSS and JS) from the respective download link of the task. This way we see a real output and variable declarations of different tasks won’t overlap.
Have a nice day and keep up the good work! 
Michael