 Finally the difference of the two squares is formed and scaled by a factor of one fourth using yet another operational amplifier.In 1980, Everett L. Johnson proposed using the quarter square method in a digital multiplier.To form the product of two 8-bit integers, for example, the digital device forms the sum and difference, looks both quantities up in a table of squares, takes the difference of the results, and divides by four by shifting two bits to the right.