Core Contents Media stated, "T-ara, who have been releasing title tracks back-to-back, will release '2013 What Should I Do' following 'Number 9'. '2013 What Should I Do' will be the main title track.
"2013 What Should I Do" is the work of Shinsadong Tiger and Polar Bear and features sampling of the theme song for the song that won the traditional University Song Festival back in 1977, Sand Pebbles' "What Should I Do?". The newly released jacket image also takes us back in time to that period with a cassette tape.
T-ara shared, "We want to create a retro song that surpasses 'Roly Poly'... We want listeners to remember the University Song Festival through this song."