After the initial payment, use it for life without any additional internal payment or advertisements~
As it is an app for studying, I did not put any advertisements.

We have systematically organized the core theories of practical skills for obtaining certifications.
- Almost all theories have been summarized, and additional conceptual explanations have been added to help understanding.

Important content is hidden and exposed when clicked
(so that you can test the memorization by yourself)

Included in the appendix of the automatic calculation program that can be helpful in practice


personal social media
https://www.instagram.com/haiyun.kim