G# add13/C
The G# add13 chord consists of the G# (Perfect unison), C (Major third), D# (Perfect fifth) and F (Major thirteenth) notes, with C as the bass note.

How to play the G# add13/C chord
- Play C as the lowest bass note in the left hand
- Find G# (Root) on the piano keyboard
- Add C (Major third) — 4 semitones above G#
- Add D# (Perfect fifth) — 7 semitones above G#
- Add F (Major thirteenth) — 21 semitones above G#
- Press all 5 notes simultaneously to sound the G# add13/C chord