After a typhoon, w trees in Haley's backyard died. If she had grown x trees initially How many more trees died in the typhoon than those that survived?
There were 3 trees in Haley's backyard initially. 

After the typhoon, w = 13 trees died and x - w = -10 trees survived. 

Therefore, the number of trees that died in the typhoon is w - x = 13 - 3 = 10.