Here’s a good way to tell how old you are. When you see “Arthur theme song,” do you think of:
1. Christopher Cross?
2. a four-eyed aardvark?
Well, if you’re 21-year-old Chance the Rapper, you’re all about the D.W., and you perform the theme from the animated PBS show in front of thousands at Sasquatch. HEY, you’re not old.