Big Calculator Free App for iPad
"Big Calculator Free was designed to take full advantage of the iPad screen offering a large display and a paper tape to keep track of your calculations. Need even larger buttons? Rotate to Portrait mode to fill the entire screen with just the calculator.
★ Large, easy to press buttons
★ Paper tape so you can see your previous calculations
★ Change the font size of the paper tape to whatever is right for you
★ Email or Copy the contents of your paper tape
★ Memory Recall button changes to display your current memory value
★ Support for percentage, square root, squared, cubed plus all the basics
★ Backspace button
★ Store state when you exit - start off right where you left off
★ Number format based on your locale settings"
This is a free app