GoodCalculator is not a iPhone calculator replacement but a new one that will be installed. GoodCalculator looks almost exactly to the Calculator in firmware 2.0 but it adds some extra options. A (+-) sign, a percentage (%) sign and a back space (<–) option.
1) Locate and install the calculator.
2) Updated calc screen.
This little app is available in the Installer.app through the iSpazio source, see our sources page.