Abstract: A mini electronic calculator adapted to assist children in acquiring the rudiments of arithmetic. The keyboard of the calculator is provided with three parallel sets of keys, the upper set being a row of digit keys for entering a first complete number, and the middle set being a corresponding row of digit keys for entering a second complete number. The lower set includes plus and minus sign function keys and an equal sign key. The calculator display is in a blackboard format and has three parallel groups of LED display stations, the upper group of which is formed by a row of digit stations for presenting the first complete number entered by actuating the keys in the upper keyboard set. The second group is formed by a lead station for presenting a plus or minus sign, depending on which function key is actuted, followed by a row of digit stations for presenting the second complete number entered by actuating the keys in the middle set.