Explain how to solve this math problem: Willow’s daughter had a slumber party with 3 of her friends.  For breakfast, they wanted pancakes.  Willow’s pancake recipe makes 1 serving of 4 pancakes.  Each of the girls wanted a serving and a half of pancakes.  Willow’s son wanted 3 servings of pancakes.  How many single pancakes will Willow make for the girls and her son?