In this section will be presented some simple calculating devices, which are not so clever, to be presented in other sections of the site, but still clever enough, to be interesting as principle or to had market success. During the second half of 19th and first half of 20th centuriy, a large number of relatively inexpensive machines were marketed to businesses and others for use in performing simple addition and subtraction. In principle, these adders and other devices could also be used for multiplication by repetitive addition and for division by repetitive subtraction. Numbers were typically entered by using a stylus to move a dial or slide. Most of the handheld devices are cheap (sold for $1 to $25 in USA). Some devices of this type have already been examined in other sections of this site, for instance devices of Perrault, Caze, Kummer, etc.