"This whole balance thinga-magig seems really familiar. It reminds me of equations!

"First, I didn't know how many cookies were in a bag. So that's the unknown, like a variable!"

x=?

"And there are 2 of them."

2x

"And there are 5 additional cookies."

2x+5

"And the 2 bags and 5 cookies equals the same amount as 11 cookies."

2x+5=11