题目

I was in the park with my elder sister, Cathy, on Friday. My sister left her jacket on a chair while we talked to some friends. When we went back to the chair, a girl in a red T-shirt was sitting there. She had some money in her hand. When she saw us, she stood up and walked away.     I asked my sister, Did you have any money in your jacket?     She said, Yes, Anna, I did.     I said, Look in your jacket quickly.     Cathy looked in her jacket, but her money was not there.     That girl stole it! I said, and we both ran after her. We caught her quickly.  My sister wa减数是42，差是46，被减数是（______）。