There were w dollars in Olivia's wallet. She collected x more dollars from an atm. After she visited a supermarket there were x dollars left. How much more money did she collect at the atm than she spent at the supermarket?

First, we'll define the supermarket variable. Let's call it s. 

s = x

This means that the supermarket variable is equal to the x variable. 

Now, we'll define the atm variable. Let's call it a. 

a = w + x

This means that the atm variable is equal to the sum of the w and x variables. 

Now, we need to figure out how much more money Olivia collected at the atm than she spent at the supermarket. To do this, we'll take the atm variable and subtract the supermarket variable from it. 

a - s

a - s = (w + x) - x

a - s = w

This means that Olivia collected w more dollars at the atm than she spent at the supermarket.