Calc is a free app available from the AppStore. It is a simple tape calculator for the iPhone. It has all the features required for a scientific or advanced calculator. The only difference between the default calculator and Calc is that Calc allows you to view your calculations and your steps as it keeps a record of it when you perform the calculations. The screenshot above will help you to understand it better. Also you can switch to advance calculator and other functions like log and squareroot etc by pressing fn. The only thing we hate? This one doesn’t have a Landscape mode!!