Abby is pretty smart. I think if I would have left her with the adding machine for a while longer she would have figured it out.
I remember when she first came to live with me. She was a tiny thing at 4 months old.
I kept the catnip in the freezer of my fridge. It's the kind that has a separate freezer door. I came home from work one day and my freezer door was wide open and all of my ice cubes were melted! I thought I might have left it ajar before I left for work and when Abby jumped onto the top of the fridge to get to the top of the cupboards that she might have pushed it open.
The next day it was the same thing. And the day after that too!
Now I knew I had made sure the door was firmly closed before I left for work and it seemed to take a bit of effort to open it once it was closed.
One day I was sitting in my living room at the computer and I heard a banging and scratching and thumping sound coming from the kitchen behind me.
I got up and looked and there was Abby hanging off the front of the freezer door and pushing herself off the door with her hind legs and swinging her body from side to side. She managed to open the door!!!
Mystery solved! I wasn't going crazy after all! Abby could smell the catnip and figured out a way to open the freezer door, but she couldn't figure out how to get inside the freezer to get at the catnip.
After that I used packing tape to keep my freezer shut. She eventually broke the habit and stopped trying once she figured out that her little acrobatic act wasn't working anymore!