Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
부정수는 특정한 값을 가지지 않는 수입니다.bujeongsuneun teukjeonghan gabseul gajiji anneun sueimnida.An indefinite number is a number that does not have a specific value.