Flash mental calculation

This app that you can practice flash mental arithmetic.
You can review the calculation process by tapping the confirmation button after calculation.
In addition, since the question which was made is saved in the past log, you can rechallenge the mistaken problem later.
The past logs are saved for 10 questions before purchase, and 150 questions can be saved after purchase.
■ Past log
Challenge mode, practice mode questions and results are automatically saved.
Touch the challenge button to re-challenge the question.
The past logs are saved for 10 questions before purchase and 150 questions are stored after purchase.