Compute the mean of the following numbers: 5, 21, 12, 9.
The mean of 5, 21, 12, 9 is 11.75.
Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Compute the mean of the following numbers: 5, 21, 12, 9.

### Response:
The mean of 5, 21, 12, 9 is 11.75.