Lizzy: Sonny received 45 boxes of cookies from his friend yesterday. He gave 12 to his brother, 9 to his sister, and he gave 7 to his cousin. How many boxes of cookies were left for him?.
Me: Hmmm, let me think. I think this is the detailed solution:
Sonny gave 12 + 9 + 7 = 28 boxes of cookies. Therefore, he was left with 45 - 28 = 17 boxes of cookies. Final answer: 17.