Update 20_sets.md

website/content/03_sets_tuples_dicts/20_sets.md

@@ -137,7 +137,7 @@ Or, you can use the built-in `sorted(sequence)` method, which will do the conver
 
 #### adding to and removing from `set`s
 
-Since a set has no order, we can't add or remove items to it by index.
+Since a set has no order, we can't add or remove items from it by index.
 
 Instead, the operations are called with items.
 
@@ -229,4 +229,4 @@ Next, let's find the intersection. We'll create a new `set` with *only* the item
 
 There are other useful operations available on `set`s, such as checking if one set is a subset, a superset, differences, and more, but I don't have time to cover them all. Python also has a `frozenset` type, if you need the functionality of a `set` in an immutable package (meaning that the contents can't be changed after creation).
 
-Find out more by reading the [documentation](https://docs.python.org/3/library/stdtypes.html#set), or calling `help()` on `set`.
+Find out more by reading the [documentation](https://docs.python.org/3/library/stdtypes.html#set), or calling `help()` on `set`.