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

How to play the A major/C# chord
- Play C# 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
- Press all 4 notes simultaneously to sound the A major/C# chord