I've got a 2.5 and 5.5 year old. I find there's LOTS of ways to teach other subjects (math, science, reading, even history!) when outside. What are your favorite ways?
With my little ones, we're often counting things--counting leaves, counting eggs, counting steps, etc. We also do a bit of multiplication sometimes when planting seeds (each of these rows have five seeds, how many seeds are there?) and adding (there's two blueberry plants and on honeyberry plants, how many plants are there?)
We talk about history of the landscape--who moved in when, why there's these huge cedar stumps with notches in them, how the landscape was formed by receding glaciers leaving big "glacial erratic" rocks, and how old the
trees might be.
We sound out words while walking and figure out what sounds they start with and what they rhyme with, and find smaller words in the big words (blue-berry has both blue and berry! What other words have berry in them?). I need to start incorporating writing, too--maybe using sticks to form letters? Or writing with
water on a dry wall or road? Or writing in the sand/dirt with sticks? We do some writing with chalk on the sidewalk. We could also look for the shapes of letters in nature!
What are ways you can think of to incorporate all the subjects with kids of all ages? What's your favorite?