Today I decided I needed to be a bit more intentional to make sure we're meeting state benchmarks and all that. I had my husband watch the kids for 45 minutes while I did some planning--basically, I tried to figure out what we're supposed to be covering this month, and ways I could teach them in a fun, intuitive way.
One of my ideas was to use sticks and rocks and chalk. I started writing out equations, like "3+5" and then put 3 rocks about the 3, and 5 rocks above the 5. My son came over and was curious to see what I was doing. At first, he was cranky because he realized it was math, but I just said, "Oh, I'm just playing. Let's see" *and I started counting slowely while pointing at the rocks* "so I have 1,2,3 .... 4, 5.." and my son exclaims "8! I got it before you even finished!"
I did an equation with sicks, and then he decided he wanted a pattern, so we did a rock equation next (he told me the one to write, 5+5=10) and then he helped me find sticks and break them up to make 10+10=20.
I then started doing 0+5, and that morphed into adding 2,3,4,5 and 6 to 5. My son was then ready for something else, so I let him play!
My daughter then started playing with logs, walking up and down them. So, I seize the moment and we started counting them and writing down the equations. I didn't focus too much on the writing, as it's not what she needs to work on. But, exposure to the concept of equations can't hurt, either! She had a lot of fun adding and removing logs from her stairs and counting them!
One of the best ways I've found, for myself, to teach/lesson plan is to first be prepared with what you want to teach. This gives you a grounding. I wanted to work on 1-digit addition, so I started with that. But, my son wanted to have me write the equations he was interested in. Why not?! So I did, and then let it morph into what he was interested in. Kids learn a lot faster and deeper when they can play a part in it. Teaching is a relationship. You give information, and they respond with learning and questions, and you adjust your teaching to their interest/patience level/and abilities. If you keep trying to teach something they're not ready for (emotionally, mentally, physically), then it will be ineffective and usually be really frustrating.
I think it's really important to hold you idea for the lesson loosely. Know your subject well, know what you want to teach... but be willing to adjust, because it's in that adjusting that the learning really occurs!