Abstract: An automatic calendar is provided which permits a regular change in the display from the end of the month to the first day of the next month to be achieved without requiring adjustment over a prolonged period of time, by employing a unique arrangement of numerals providing a display of date. The calendar comprises a unit's day display member having an indication of numerals in the sequence of 0, 1, 1, 2, 3, 4, 5, 6, 7, 8 and 9 at an equal interval, and a tens' day display member having an indication of numerals in the sequence of 0, 1, 1, 2, 2 and 3 or a repeated sequence thereof.

Abstract: A fully electronic car clock with digital display is provided in which the counter circuit of the car clock is connected to a car battery through an engine key switch to be driven therefrom, and the clock display is interlocked with the engine key switch so as to be energized or deenergized in accordance with the ON-OFF position thereof in order to avoid draining the battery. A method of time setting the car clock is also proposed.