From the proud parent department:
My wife made cookies. Chocolate chip cookies.
The cookies were in a semi-translucent plastic storage container on the kitchen counter. Late one evening there were three cookies left and I indulged and ate two.
The next morning at breakfast our three and a half year old son looked for the cookies and announced in alarm “Two are missing!”
Hmm. Apparently not only was he counting the cookies, he can subtract as well.