can you prove it? A child could prove it, put 2 marbles on a paper then put a plus sign, now put to more marbles on the other side and then count the marbles, this is how we learned addition in kindergarden at 5 and this is how they did it with produce, they memorized a full count of multiple thing, then they memorized the number of barrels times how many total barrels to speed up instead of paying for each barrel of whatever you were buying individually. Man if you require college for what is know to 1st and second graders the world went full retard and you never go full retard. Late reply but relavent to me at least.