Whether you are confident in your memorization ability or not, please try it out with this app. You can feel free to test your memorization ability with people from all over the world at any time. You can also customize the speed and number of digits, so you can train at the level that suits you. Please try the world ranking when you get the ability. Rankings are also divided into levels according to ability. You may be able to aim for the top ranking in daily training. Please use it to pre