Last week Fred had w dollars and Jason had x dollars. Over the weekend Fred delivered newspapers earning y dollars and washed cars earning z dollars. How much money did Fred earn over the weekend?
First, we need to find out how much money Fred had last week. We know that he had w dollars, and we know that Jason had x dollars. This means that the total amount of money between the two of them was w + x dollars. 

Now, we need to find out how much money Fred earned over the weekend. We know that he delivered newspapers earning y dollars and washed cars earning z dollars. This means that the total amount of money he earned was y + z dollars. 

Now, we need to find out how much money Fred had in total after the weekend. To do this, we need to add the money he had last week to the money he earned over the weekend. We know that he had w + x dollars last week, and we know that he earned y + z dollars over the weekend. This means that the total amount of money he had after the weekend was (w + x) + (y + z) dollars. 

Therefore, the answer (symbolic expression) is: 

(w + x) + (y + z)