GEM calculator converted for Indian currency, 1912.

Stylus-operated Indian currency adder, wooden backboard with handmade varnished card face inscribed 'R.G.W. 24.2.12'. The GEM calculator was originally patented in 1890 as a simple device for the addition of English money. Numbers are added by inserting a stylus against the figure and pulling downward. This later version is adapted for Indian currency.