A 7/E
The A 7 chord consists of the A (Perfect unison), C# (Major third), E (Perfect fifth) and G (Minor seventh) notes, with E as the bass note.

How to play the A 7/E chord
- Play E 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 G (Minor seventh) — 10 semitones above A
- Press all 5 notes simultaneously to sound the A 7/E chord