ABSTRACT
This chapter discusses three examples of the produced ordinariness of ordinary action— one involving arithmetical calculations, one concerning the play of checkers, and one regarding the local followability of a mathematical argument. The type of perception arises from within the circumstances of playing checkers: players have to be able to see such adventitious exchanges in complicated board positions. That checkers is played in accord with the rules— not that players are literally following the rules— is the observable phenomenon and a social requirement of playing. Much like the illustration the naturally accountable, practical adequacy of a description of a proof is wedded to the proof made available through that description. Whatever else the student's annotations in the subtraction problem did, they kept her place in her developing calculation. Keeping place is an extremely ordinary aspect of doing arithmetic; it's so ordinary that it seems not to merit any comment.
