Strengthen the response and sensitivity to numbers in English language. Under the continuous special training and testing, improve the rapid and accurate recognition of digital content in foreign language listening tests (such as TOFEL, IELTS, ..). * Digital content generation is based on the TTS engine, so the device system must support the standard TTS engine. It is recommended to use google TTS. * Classified training for various types of numbers. * Easy to control the difficulty of training