This is a memorization app I created to study to become an industrial safety engineer in my spare time, such as on the subway and bus.

My method of use is
1. First, memorize the problem and answer.
2. Write down the problem in the app.
3. Be sure to memorize the answer and write it down in the app.

There are probably mistakes that you can make by writing down questions and answers in advance and memorizing them based on what you wrote in this app.
But try it like I used.

Before writing it down in the app, you can memorize it once while writing it in the app, and then memorize it in this app and check it once while writing the answer. And whenever you have free time on the bus or subway, try using it to easily check what you have memorized and review it over and over again.

I passed the industrial safety engineer exam the first time using this method.

I hope you get good results.