A+ is the fourth extended play by South Korean singer Hyuna. The EP consists of five tracks and incoporates Pop and Hip-Hop music genres. It was released for digital download by Cube Entertainment and Universal Music on August 21, 2015. The physical album was released three days later on August 24. To promote the EP, Hyuna appeared on several South Korean music programs, including Music Bank, Show! Music Core and Inkigayo. "Roll Deep" was released at the title track for the EP.

On June 4, 2015, it was announced that Hyuna was preparing for her solo comeback in August. On August 9, Cube Entertainment released a trailer filmed in Los Angeles for her fourth mini-album A+, which was released on August 21. On August 13, "Because I'm the Best" (or "Roll Deep" in international markets) featuring Jung Ilhoon of BtoB was announced as the album's title track.

On August 20, the music video for "Because I'm The Best" was released via the 4Minute YouTube channel, followed by a racier 19+ version of the video deemed the "Original Version" on September 6.

On September 14, 2015, Hyuna released a short music video for the a promo single and intro track "Run & Run".

A+ entered and peaked at number 5 on the Gaon Album Chart on the chart issue dated August 22–29, 2016. In its second week the mini album fell to number 33, dropping the chart the following week.A+ charted at number 15 on the Gaon Album Chart for the month of August 2015 with 7,387 copies sold.

The title track "Roll Deep" entered at number 32 on the Gaon Digital Chart on the chart issue dated August 22–29, 2016 with 80,086 downloads sold and 803,443 streams in its first two days. In its second week, the song peaked at number 13 with 107,723 downloads sold and 2,599,263 streams in its first full week. The song spend a total of 3 consecutive weeks on the chart. "Roll Deep" charted at number 44 on the Gaon Digital Chart for the month of August 2015.

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