Introduction to Integers

I LOVE coming at math backwards - doing an activity that at first seems unrelated to math but by the end the learner has "figured out" an easier way or a short cut - which is the math I wanted them to learn in the first place. I did this activity with my 5 year old and my 8 year old together. They both enjoyed it and had NO idea they were learning "Negative Numbers."

I drew a picture of the ground with a ladder going from below the ground to above the ground. The ladder had 5 rungs below and these were blue, and 5 rungs above and these were red. See the image below. Then I put a lego star wars storm trooper "ground level" or 0.



Then I told the boys that a creature was chasing the storm trooper, one was coming down from the top and one coming up from the bottom.

me: "If the storm trooper moved up 2 and then down 4, which rung would he be at?"
boys: "At 2!"
me: "Which 2?"
boys: "The 2 that is below. The "below 2"!"
me: GOOD!

I continued to ask them these kinds of questions and the storm trooper moved up and down that ladder until my 5 year old was done and left the game. Then I told my 8 year old a little secret. I told him that mathematicians use "below numbers" all the time, but they call them negative numbers. And they use "above numbers" but call them positive numbers. Then I did a few more problems with him using the new terms.

me: "If the storm trooper moves positive 2 and then negative 5, where will he be?"
boys: "below 3. Oh! I mean negative 3."

SO FUN to see him adding integers and not even know it!
The next step will be to write down a few "subtraction" or integer problems and see if he can move the storm trooper to the right answer just using the numbers and not the words. (That's tomorrow's game:)

I'll start with simple subtraction problems, and then introduce the subtraction problems he thinks he "can't" do - the ones that are really integer problems. As below.
8-3
2-1
4-6
2-5

We'll see what happens! Hopefully this won't backfire with him correcting his 2nd grade teacher telling her "yes you can subtract 5 from 3! It's negative 2!" (Of course, I couldn't be more proud if he did ;)