The <1160 and 1162 Electronic Calculators incorporate two calculating concepts that result in special benefits for the operator. The first is the use of one key to enter the first number in any calculation. Separate keys for entry of a divisor, dividend, multiplier or multiplicand have thus been eliminated. The result is keyboard simplicity, ease of operation. The second concept is the use of the stacking principle. The stacking principle is a special register organization that allows for automatic retention of two intermediate answers. Thus, in multi-part problems, the operator need not to write down individual answers and re-enter them to obtain a final answer. Same as the SINGER: 1162, but not having a Square Root function