Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 Kurt的旧冰箱每天用电费0.85美元。他最近买了一台新的节能冰箱，每天只需0.45美元的电费。Kurt在一个30天的月份里能省下多少钱？


### Response:
 旧冰箱每天用电费0.85美元，所以30天用电费为0.85*30 = $<<0.85*30=25.5>>25.5。
新冰箱每天用电费0.45美元，所以30天用电费为0.45*30 = $<<0.45*30=13.5>>13.5。
在30天里，Kurt用新冰箱省下了25.5-13.5 = $<<25.5-13.5=12>>12美元。