"Reading, Writing, and Arithmetic" is the motto of bygone days.
Here's a short list of topics - with a few sub-topics - that used to be more common in incubators of learning.
- Communications (verbal/non-verbal, mass/personal, imply vs. infer)
- Economics (Types, Uses [freedom/tyranny], foundations, Supply & Demand)
- Personal Finance (Planning, Budgeting, Investing, Saving)
- Philosophy (World view, Notable "original" thinkers)
- Civilizations (First, Current, Socialization, Purpose)
Adding the enjoyment of learning and studying these subjects is without a doubt valuable and recommended.
There are resources/curricula available - online, and in the public library, and in the libraries of homeschoolers nearby - which can provide a quick start for learning. Focus on enjoying learning how valuable...and relevant...these topics are to each of us.