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

### Instruction:
 莎莉买了3个相框，每个相框花费了她3美元。她用一张20美元的钞票付款。她找了多少零钱？


### Response:
 莎莉的3个相框花费了她3 * 3 = <<3*3=9>>9美元。
莎莉用一张20美元的钞票付款，所以她找了20 - 9 = <<20-9=11>>11美元的零钱。