Provided are digital processing apparatuses and techniques for estimating the fractional exponentiation of the base number 2, i.e., 2f where f is a fractional value. In one representative embodiment, a calculation is made of a folded quantity, which is equal to 1−f if f is greater than a specified threshold and is equal to f otherwise; then, a function of the folded quantity is calculated; and finally, the function of the folded quantity is subtracted from the fraction f and 1 is added. In another embodiment, 2f is approximated by calculating 1+f′ in the binary numbering system.