How do your kids learn math?

I get asked a lot of questions about homeschooling and unschooling.  One question I've been getting more recently is, "How do your kids learn math?"  And, "What about things like algebra and calculus?"  Honestly, I have no idea about algebra and calculus.  I never took calculus and algebra never seemed like a big deal - it was a different way to figure things out in the world, but it didn't seem especially difficult.

As far as math in general is concerned, that's hard to describe.  I could describe things we do that are math, or require some figuring, but we obviously don't follow a linear curriculum.  I would consider the picture above to be about math - Julian was inventing different bugs that lived in an underground world (much like a particular Minecraft mod).  When Julian and Oliver organized their stuffed animals in piles of big, medium and small - that was sorting, and that's math.  The patterns that Oliver is always making on paper, with Legos, with K'nex, in his head, with the hose water on the side of the house, those things are all math because patterns are math.  When my kids listen to music, they are, in a way, listening to math.  You can't learn how to read music without also learning patterns, fractions, and probably more that I can't think of right now.
Of course, there's also the regular counting of things to make sure they both got the same amount, or figuring out how to divide things up so they get both get an equal share, or figuring out how many of what chores they'll have to do to earn enough money to buy their next "Mixel."
This all happens "naturally," but it doesn't just happen.  As an unschooling parent, one has to see life as learning - it's all learning, there is no summer break, and no cramming for finals (unless you decide to go to school).  You are learning all the time.  So when my kids ask a question, a lot of times I don't just give an answer and leave it at that.  Most of the time I try to show them the answer, walk them through my thinking processes to illustrate how I got there.  Unless I see their eyes starting to glaze over, in that case I quickly shut up and give them the answer.  There's no point, I know they'll get it when they actually want or need to know it.  I know this because this has happened over and over again.
At this point maybe I should be asking people, "How would my kids not learn math?"