docs(letter-space-number): Add examples

subjects/letter-space-number/README.md

@@ -4,6 +4,13 @@
 
 Create a function named `letterSpaceNumber` that accepts a string; returning an array with every instance of a letter, followed by a space, followed by a number, only if that number has only one digit, and is not followed by any letter.
 
+### Examples
+
+```js
+console.log(letterSpaceNumber('example 1, example 20'))
+// output: ['e 1']
+```
+
 ### Notions
 
 - [RegEx Shorthand Character Sets](https://github.com/ziishaned/learn-regex#3-shorthand-character-sets)