Sổ tay công thức: Toán Lý Hoá, developed by Study Smart, is a free educational application available for Android users. This app is designed to help students and professionals quickly access formulas based on subjects, topics, or keywords. The app is also available for iOS devices.

The app's content is for reference purposes only and has been compiled from various sources on the internet. However, the formulas have been verified by a few teachers who teach the subjects. The app's interface is user-friendly and intuitive, making it easy to navigate and find relevant formulas. Users can also save their favorite formulas for quick access. The app does not require an internet connection, making it accessible anytime, anywhere.