Complex sentence: The same day the group held their "Playing with Girls' Generation" fan meeting with 10,000 people at the Yoyogi National Gymnasium, the group performed the single along with "Gee", and "Oh!".
Split into simpler sentences: The same day, the group held their "Playing with Girls' Generation" fan meeting with 10,000 people at the Yoyogi National Gymnasium. The group performed the song along with "Gee" and "Oh!".