If you are learning Japanese you might find it difficult to understand numbers when native speakers use them in conversations. This tool will help you improve how quickly you are able to parse numbers. It will play the audio of a number in Japanese and you will have to type the number in the input field in digits. If the answer is right you will hear a next number. The numbers are completely random which means that you with enough practice you will be able to tackle any number.
If you are not familiar with the numbers yet you can take a look at the number reference guide which also includes audio.
There is also the option to practice different ranges of numbers. If you struggly with big numbers for example you can use that as an option to only practice bigger numbers. Similarly if you are quite new to the language and still learning the numbers you may find it useful to narrow down the scope and introduce new numbers slowly so you don't overwhelm yourself.
The streak will count when you answer the question quickly enough. If you are too slow your streak will go back to 0.
For replaying audio you can also use the 'R' key instead of pressing the button, making it possible to play this game without using your mouse. Similarly you can also use 'Q' to reveal the answer.
When practicing with bigger numbers you can also enter the letters 'k' and 'm' to replace 000 and 000 0000. For example, the number 162 000 can be inputted as 162k.