How do you X Out - Windows 8

Today, my son used my Windows 8 laptop. This is what his reaction was.

"This is creepy"

"How do you X out"

This is what I got from my 10 year old 4th grader. 

He had to go online to do his homework and I have him logged into my Windows 8 laptop. He logged in just fine and clicked on IE Metro style app.

After little bit of struggle, he found the URL textbox and shouted, "this is creepy".

He was quite for about 45 mins and then he was done, his next question was, "How do you X out". 

I said, WIN+F4 to close an app. Here is a list of Windows 8 Shortcut Keys here >

That was it.

Not bad. huh?