There are many myths about the way you are supposed to manage an iPhone. The largest one is currently using a hairdryer to dry the device. As opposed to drying out all the water that has gotten about the phone, doing this will only drive water more into the phone. Another myth is that the iPhone 5 car charger spoils your phone battery, this is all wrong.
Use your iPhone's calculator when you really need to execute a math function. It's a standard calculator with the phone used vertically as well as a scientific calculator when it is turned to horizontal.