Addition of two or more sets combines the items of different sets into a single set object. For example, the addition of `{1, 2, 5}` and `{2, 6, 3}` results in `{1, 2, 5, 6, 3}`.

In Python, you can add (combine) sets in the following ways.

## Use set.union() to Add Sets

Call the `set.union(set1, set2, ..., setn)` method with the set objects that need to be combined into a single set.

``````>>> set1 = {1, 2, 5}
>>> set2 = {2, 6, 3}
>>> result = set.union(set1, set2)
{1, 2, 3, 5, 6}``````

To combine more than two sets, pass the set objects as parameters to this method.

``````>>> result = set.union({1, 2}, {5, 7}, {8, 0})
{0, 1, 2, 5, 7, 8}``````

## Use | operator to Add Sets

Specify the sets separated by the `|` operator to add them to a single set object.

``````>>> set1 = {1, 2, 5}
>>> set2 = {2, 6, 3}
>>> set3 = {9, 1}
>>> result = set1 | set2 | set3
{1, 2, 3, 5, 6, 9}``````

## Use set.update() to Add Sets

Call the `set1.update(set2)` method with the second set object as `set2` to add items of `set2` to `set1`.

``````>>> set1 = {'a', 'b', 'c'}
>>> set2 = {'d', 'e', 'f'}
>>> set1.update(set2)
>>> set1
{'f', 'd', 'e', 'b', 'c', 'a'}``````