Blessi Can Subtract

I think I am teaching my horse Blessi how to subtract. We do some clicker training. If I reward him with three peanuts and two drop to the ground, he will search through the dirt for two nuts. We are not continuing with training until he gets those two specific nuts. I have tried giving him substitute peanuts but that doesn't work. Either he finds the missing two nuts by shifting through the sand or I bend down and retrieve the missing peanuts. He does well with subtraction of amounts of 5 and under.

As Blessi sings to the Meghan Trainor tune, "Because you know I’m all about that nut ‘Bout that nut, no trouble. I’m all about that nut all about that nut no trouble"