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
자북은 나침반의 방향을 결정하는 데 중요합니다.jabuk-eun nachimban-ui banghyang-eul gyeoljeonghaneun de jungyohamnida.Magnetic north is important for determining the direction of a compass.