Khan Academy is a fun tool. But I don’t believe it replaces teaching. The Washington Post questions it too. However, in a family of 4 learners, its really hard to get the individual time. This way kids can explore on their own.
An excellent foundational problem solving spiral based approach to mathematics.
Storing my lists on spelling city is great. Kids play games on material I gave. Win-Win.
This starts at a high, 3rd grade level. I will walk through things with my kids together until I know they have met that level.