The Percentage Calculator

The script asks users to fill in any 2 of 3 fields in one of several sentences (for example: x% of y is x). As user fills in these fields, the 3rd field and all fields in other, related sentences are filled in automatically. The tool can be embedded on external websites via a short html code. It's valid HTML5 (but of course works just fine on websites that don't use HTML5). It can be used simply to calculate percentages or for educational purposes (for example to provide an interactive element to online lectures on percents).