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?
Olivia's wallet: w dollars

Olivia's wallet after collecting money from ATM: w + x dollars

Olivia's wallet after visiting supermarket: w + x - x = w dollars

Olivia collected x more dollars from ATM than she spent at supermarket.