“EVERYONE'S pencil should be on the apple in the tally-mark chart!” shouts a teacher to a class of pupils at Harvest Preparatory School in Minneapolis. Papers and feet are shuffled; a test is coming.

Answer: It’s a way of counting on paper the same way we used to with our hands. In around the 1850s, you would have a 'tally man' to assist you with whatever you were counting and he would prove he ...