Editing Slide calculator (section)

== Design ==
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The Addiator is composed of sheet-metal sliders inside a metal envelope, manipulated by a stylus, with an innovative carry mechanism, doing ''subtract ten, carry one'' with a simple stylus movement. Some types of Addiators can also handle negative numbers (with a complementary bottom window or by providing a subtraction mode on the back side of the device).

The Addiator also handles non-decimal measurements, like feet and inches, or pre-decimalization [[pounds, shillings, and pence]]. Addition and subtraction require different "screens", handled by turning the instrument over, or flipping a front panel, or, later, by extended sliders and an extra lower panel. Although not always advertised (e.g., the [[Magic Brain Calculator]] mentions "add, subtract, multiply" on its front plate), procedures exist for multiplication (by repeated addition or by individual digit multiplications) and division (e.g., by repeated subtraction, or use of additions combined with [[complementary numbers]]).

More expensive versions have a built-in [[slide rule]] on the back.