What is the difference between Accounting, Finance and Economics?

Sometimes people may wonder what are the differences between Accounting, Finance and Economics? To my understanding:

  1. Accounting is about what had happened in the past.
  2. Finance is about what may happen in the future.
  3. Economics is about what should happen in the future.

Understanding the difference may help us to use what has happened in the past to help us predict what may happen in the future and use what should happen as a guide.

What do you think?