Teaching Two or More Children

I thought I would post this question.  How do you teach two or more children?

I started homeschooling an hour or two hours a day when Noah was 4  and Hannah was 2 out of necessity.  We were living in a tiny apartment with my mother in law and we had to do something structured since we only sent Noah twice a week to a mother's day out preschool. I wasn't going to teach Hannah but then she wanted to learn and join in.  So, I got her her own easier workbooks so she could something similar to what Noah was doing.  

They seem to enjoy learning together so I continued on like this and eventually we went overseas.  

Now I teach Bible, science, and history with the kids together. We usually do those subjects first and then do independent work last.  Sometimes we switch for a change.  I teach the level between them for those subjects.  Then, I teach the other subjects spelling, math, grammar/writing, and reading separately according to their level.  I usually give one independent work and then teach the other a subject that needs teaching a new concept.

What do you all do with your children?  How do you teach multiple children?  How is your day structured?  Or has anyone had a better experience teaching their children on different levels for all subjects?

When the children get older, do you teach the children history and science separately?  I would like to hear people's experiences.  :) I think it's helpful to hear from those homeschooling for a while especially! 

 If anyone has any other questions to post, please feel free to do so since maybe you have a question that someone else has as well.