Question-How do you homeschool many children at the same time?
One thing that helps for us is after we had been going for a couple years I began to let the environment and rythms do much of the work.
For instance, instead of reading a geography text we stuck a world map under plastic on the table. Within two years my older kids could pretty much tell you where ever place in the world is and what it is next to. We have also stuck artwork under the table, I wrote about that here- http://melissacalapp.blogspot.com/2010/01/child-sized-masterpieces-level-3.html.
I have also trained all of the children to listen to tapes before bed and then I bought tons of History, scriptures, poetry, musician biographies, and works of literature on tapes and CDs. This morning I mentioned for the first time George Washington Carver, and got a huge explanation of who he was and what he did, not because I had taught it, but because they heard it on tape.
One of the rythms we have also that works well for us, is first thing in the morning I roll the kids out of bed and start reading to them--this morning it was the last chapter of "Gulliver's Travels," and then a chpater in "Story of the World," about Africa after World War II, which was followed by a discussion of racism, inequality, and then somehow how one should pick who they marry and what to look for, and then what kind of jobs can be done from home, so they can be their with their families as much as possible. This rythm of first reading and then letting any discussions come, allows a lot of learning to occur early in the day, since I work from home and need afternoons for that.
If I keep going I'll start rambling, so I will just stop and say. Homeschooling large families does work for the parent willing to deviate from the grade level paradigm, and there is a lot of satisfaction in it.