Danny collects bottle caps and wrappers. He found w wrappers and x bottle caps at the park. Now he has y bottle caps and z wrappers in his collection. How many more bottle caps than wrappers did danny find at the park?
Danny found w wrappers and x bottle caps at the park.

Now he has y bottle caps and z wrappers in his collection.

We need to find out how many more bottle caps than wrappers Danny found at the park.

We can do this by subtracting the number of wrappers he has now from the number of wrappers he had at the park and subtracting the number of bottle caps he has now from the number of bottle caps he had at the park.

We need to be careful with the order of operations.

We need to subtract the number of wrappers he has now from the number of wrappers he had at the park first and then subtract the number of bottle caps he has now from the number of bottle caps he had at the park.

Therefore, the answer (symbolic expression) is: 

(x - z) - (w - y)