calCOOLator is a free calculator app developed by This Metal Sky for Android 9.0. This calculator app is unique in the sense that it doesn't have an equals button. Instead, it has two text entry fields - one for entering an expression and the other for providing a running total. You can switch between these fields at any time, and use the result of a previous calculation in a new one.

The app has a simple and intuitive interface, making it easy to use for anyone. It provides all the basic arithmetic operations such as addition, subtraction, multiplication, and division. You can also use parentheses to group expressions and perform complex calculations. The app also supports scientific notation and trigonometric functions.

Overall, calCOOLator is a great tool for anyone looking for a simple yet unique calculator app. Its user-friendly interface and ability to perform complex calculations make it stand out from other calculator apps in the market.