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

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