This is THE BEST calculator for iPhone, iPad and iPod touch!
・Dual-line display - shows the input and result at the same time
・History tape - saves every calculation, time and date stamped
・Memory buttons - shows its value on the display
・Percentage and backspace button
・6 layouts (3 portrait, 3 landscape)
・11 color themes
・Multi-line input for really long equations
・Automatic scientific formatting
・Label any calculation in the history tape
・E-mail a calculation or the entire history tape
・iOS 9 Split View
・Swipe down to see the history tape
・Swipe left or right on the keypad to switch between basic and scientific keys
・Swipe left on the display to backspace
・Swipe right on the display to clear
・Tap & hold on the result to copy
・Tap & hold on the input to move the cursor, copy, paste, convert to E-notation
・Light Tape Background
・Show Layout Button
・Show Memory Buttons
・Replace ÷ Button With /
・Replace E Button With 00
・Show Thousands Separators
・Minimum Decimal Digits
・Maximum Decimal Digits
The only difference is that the Free version has ads.
No, you only have to pay once and then you can download it again for free onto all of your devices.
The app is universal and works with both the iPhone and the iPad.
You can also share your purchase with others in your family if you have Family Sharing enabled on your account.
For more information about Downloading Previous Purchases and Family Sharing, please visit Apple at https://support.apple.com/billing
The Paid version of the app is a totally separate app, so look for a new icon on your device without the word Lite on it.
Start using the Paid version from now on, and delete the Free version from your device so that you do not open it by mistake.
Here is what the two different icons look like for reference: