Abstract: In a stop watch, when a switch is depressed, hands are operated to start timing. Every time a split time switch is depressed, the time intervals between time points at which the split time switch is depressed are sequentially stored in a memory. Therefore, when the switch is re-depressed, the stop watch terminates its time measurement. A plurality of split times up to the end of time measurement can be reproduced, from the latest split time to the earliest split time.

Abstract: The image reproduction apparatus of the present invention can make a copy of images written or drawn on a board as well as a copy of images of an original provided on an original table. The image reproduction apparatus comprises a board portion and a copying portion. The optical information of images written or drawn on a board is supplied to the copying section through an optical system. The copying section moves between a position where the image reproduction is performed by the above optical information and a position where an ordinary copying of the original is performed. Thus, according to the present invention, the copying section moves between said two positions.

Abstract: A calculator in which when numerical information and function information are sequentially input using ten keys and function keys of a key input section for obtaining a calculation result according to a calculation formula, the input information is stored in a memory. The operation is then performed and, simultaneously, a character formula universally representing the calculation formula with the input numerals replaced with characters is prepared. This character formula is displayed by the display section so that the input condition may be easily confirmed and input errors may be prevented with certainty.