# Problem
Sets can be combined using mathematical operations.
The union operator | combines two sets to form a new one containing items in either.
The intersection operator & gets items only in both.
The difference operator - gets items in the first set but not in the second.
The symmetric difference operator ^ gets items in either set, but not both.
```python
# merge multiple sets
set().union(*sets)
first = {1, 2, 3, 4, 5, 6}
second = {4, 5, 6, 7, 8, 9}
print(first | second)
print(first & second)
print(first - second)
print(second - first)
print(first ^ second)
```
# References
- https://www.programiz.com/python-programming/methods/set/intersection
- [Learn How to Combine Sets in Python - Python Pool](https://www.pythonpool.com/learn-how-to-combine-sets-in-python/)