"Come by!" called the farmer. He heard the sheepdog before he saw it, and cursing his failing eyes, reached out to pat the dog's head roughly. "There's a good boy." Then he knelt down and said to the dog, "I can't count them blasted sheep any more. I need you to count them for me. Can you do that for me, boy?"
The dog barked twice and ran off, returning after a couple of minutes.
So, said the farmer. How many sheep was there then?
40, replied the dog.
What? How can that be? exclaimed the farmer. I only bought 38!
I know, said the dog. I rounded them up.