给定一组数字，编写Python代码以计算它们的平均值、最大值和最小值。


[23, 45, 67, 89, 12]
```python
nums = [23, 45, 67, 89, 12]

avg = sum(nums) / len(nums)
print("平均值:", avg)

max_num = max(nums)
print("最大值:", max_num)

min_num = min(nums)
print("最小值:", min_num)
```