Calculator-00 Simple useful is a free calculator application designed for Android users. It is created by Yasuhiro Kawagoe and falls under the Business & Productivity category. The app has a simple and user-friendly interface that allows users to pull out and enter numbers smoothly. It has added "00" and adjusted key layout for better user experience.

In addition, the app has a swipe-down feature for history and swipe-left for function calculation. The app also offers widgets that can be used on the home screen for quick access. Overall, the Calculator-00 Simple useful is a great application for those who are looking for a simple and efficient calculator.