Danny collects bottle caps and wrappers. He found 20 bottle caps and 20 wrappers at the park. Now he has 34 bottle caps and 31 wrappers in his collection. How many bottle caps did danny have at first?
Danny finds 20 bottle caps and 20 wrappers. So far, he has 20 bottle caps. 

He then finds 14 more bottle caps and 11 more wrappers. So far, he has 34 bottle caps and 31 wrappers. 

We want to know how many bottle caps Danny had at first, so we want to go back one step. 

Danny had 20 bottle caps at first.