it is extremely funny to see him do math what was the "normal" way for him (but completely unrecognizable to the modern viewer),
and then go on to make fun of the subtraction algorithm that most people reading this post are probably intimately familiar with, as something strange and foreign and new and difficult to understand (and i kind of pick up that maybe he is being self aware, and knows that it's not actually all that hard, and that the outcry was silly)
the real comedy is the cyclical nature of it all. closed-minded parents brought up on "new math" are now freaking out as their kids learn common core math.
