Percentage calculation app for iPhone and iPad

You make purchases and you want to know the percentage discount in sales.
You need to know the value of a tax,Like VAT to make purchases in a shop where prices are reported duty-free.You have a calculation to do to determine the percentage of one ingredient among others in a product.
You want to do percentage calculations for any other reason;

This application is for you.

You enter your base number in a screen and then the percentage of that number you want to calculate.
The result appears in the right screen giving you 2 indications to choose from:
- one of the results is calculated with the subtracted percentage (-), for sales for example
- one of the results is calculated with the percentage added (+), for the sums with taxes