Problem
When a school teacher is out sick/on vacation/etc., the school has to quickly find a substitute teacher and ask them to come in, which is done by going through an existing list of approved professionals and connecting with them over the phone to see if they are available and how fast they can get there, which seems like a very inefficient and unfair process.
Solution
A one-stop marketplace with a full list of substitute teachers with reviews/ratings, availability, chat, etc.