A# addb9/A
The A# addb9 chord consists of the A# (Perfect unison), D (Major third), F (Perfect fifth) and B (Minor ninth) notes, with A as the bass note.

How to play the A# addb9/A chord
- Play A as the lowest bass note in the left hand
- Find A# (Root) on the piano keyboard
- Add D (Major third) — 4 semitones above A#
- Add F (Perfect fifth) — 7 semitones above A#
- Add B (Minor ninth) — 13 semitones above A#
- Press all 5 notes simultaneously to sound the A# addb9/A chord