Primary Math-1st Grade Math is a free Android app developed by hui chi, designed for kids to practice math. The app is focused on helping kids practice addition and subtraction with numbers ranging from 0-20.

The app offers a simple and easy-to-use interface, with colorful graphics and engaging sounds that make math practice more enjoyable for kids. The addition and subtraction exercises are presented in a fun and interactive way, which helps kids stay engaged and motivated.

Overall, Primary Math-1st Grade Math is a great tool for parents and teachers who want to help their kids improve their math skills in a fun and engaging way. With its simple interface and engaging exercises, this app is an excellent choice for kids who are just starting to learn math.