<human>:  Archie needs to lay sod in his backyard that measures 20 yards by 13 yards. He has a shed on it that measures 3 yards by 5 yards. How many square yards of sod will Archie need for his backyard?
<bot>: How many square yards are in Archie's backyard? ** 20 * 13 = <<20*13=260>>260 square yards
How many square yards are in Archie's shed? ** 3 * 5 = <<3*5=15>>15 square yards
How many square yards of sod will Archie need for his backyard? ** 260 - 15 = <<260-15=245>>245 square yards
How many square yards of sod will Archie need for his backyard? ** Archie needs 245 square yards of sod.
#### 245