1. A non-transitory memory device storing instructions that, when executed by a processor, cause the processor to: (i) display, on a screen, a respective set of symbols for each of a plurality of denominations of money, wherein each symbol has an unselected appearance and a selected appearance, and wherein each set includes a respective quantity of symbols; (ii) receive indicia of selection of a symbol, the selection of the symbol provided by user through an input device; (iii) update the appearance of a symbol on the screen in response to the received indicia of selection; and (iv) revise the respective quantity of symbols in each set so that no first particular set of a relatively lower denomination has zero unselected symbols when a second particular set of a relatively higher denomination has more than zero unselected symbols; (v) display a plurality of numeric values on the screen, the plurality of numeric values comprising: (A) a first total for all symbols selected; and (B) a difference between a goal amount and the first total; and (vi) update the display of the plurality of numeric values in accordance with the received indicia of selection.