Calc-12E

Calc-12E... Written by the same mathematician who wrote the HP-12C financial algorithms, Calc-12E marries that undisputed computational heritage with the unique features that make the iPhone the premier tool for business.
The mathematical backbone of the 12C extended to 15 digits of precision (displays up to 13) Bond calculations performed with 15 digit precision "Always on" display of the financial registers or the stack.