Abstract: A calender (10) has a plurality of leaves (12) each representing a month of a year. Each leaf (12) has an outer transparent cover forming a pocket for inner and outer sheets (24,26). Inner sheet (26) has numerals therein in a precise pattern which are registered with apertures (30) in the outer sheet (24) to represent the days of the month. Inner sheet (26) has seven columns of numerals and is slidable a maximum distance no greater than the width of one column in order to adapt calendar (10) for all years.