Can you give me some step-by-step instructions for this math problem: A farmer is baling hay in their field. Each hour the farmer makes 5 bales. At the same time, a truck is picking the hay bales up. Each hour the truck picks up 3 bales of hay. If the farmer and the truck driver put in a 6 hour day, how many bales of hay are left in the field?
The farmer makes 5*6= 30 bales of hay.
The truck takes away 3*6= 18 bales of hay.
There are 30-18= 12 bales of hay left in the field.