The album was released digitally on October 10, including the title track "
Number 9" (넘버나인) and b-side track "Because I Know" (느낌 아니까) and their music videos. "Number 9" is an electro-pop dance song with sad lyrics and melody. It was choreographed by Yama & Hotchicks, who also choreographed "
Bo Peep Bo Peep". "Because I Know" is a mid-tempo song with an acoustic feel. A repackaged edition of the EP,
Again 1977, was released on December 4, 2013. It contains two new songs, "Again 1977" and "
Do You Know Me", a remake of Sand Pebbles' 1977 hit, "What Should I Do". T-ara held a series of fan signing events in
Suncheon and
Gwangju, starting January 6. Notably, for the first fan sign, over 5,000 fans gathered around the venue, but for safety concerns, only 1,000 people eventually were allowed to attend. Actors
Son Ho-jun and
Yoon Jong-hoon attended the event. The EP was re-released as special album on December 14, 2013 titled
White Winter in addition to a Christmas song, "Hide and Seek" and an alternate version of the song featuring the same lyrics but slightly different instrumental. In 2016, Chinese girl group "Miss Mass" released a remake version of the song in Chinese. == Commercial performance ==