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

### Instruction:
Steve has 25 socks. He has 4 pairs of socks that match, and all the others don't match. How many mismatching socks does Steve have altogether?

### Response:
Steve has 25 socks, and 4 pairs of socks that match. So he has 25-4=<<25-4=21>>21 mismatching socks.
#### 21

