James wants to hang crepe-paper streamers from his backyard fence for his birthday party. His backyard fence is a rectangle that measures 20 feet on the long side and 15 feet on the short side. How many feet of crepe paper does James need to buy?
First figure out how much crepe paper James needs for the long sides. Since there are two long sides, multiple the side's length by 2: 20 feet * 2 = <<20*2=40>>40 feet
Now do the same multiplication to find out how much crepe paper James needs for the short sides: 15 feet * 2 = <<15*2=30>>30 feet
Now add the amounts for the short and long sides together to find the total amount of crepe paper needed: 40 feet + 30 feet = <<40+30=70>>70 feet
#### 70