If you're an intermediate or advanced pianist, you know that a chord is usually composed of at least three notes. The basic chord is made up of the first, third and fifth notes in a scale and can be inverted to create different sounds. However, an A5 chord uses only two notes, as does any basic fifth chord. The A5 chord is played using the first note of the scale, an A note, and the fifth note in a scale, the E note. You can play these in any order with the left or right hand.
Place the thumb of your right hand on the first A key above middle C. Middle C, also known as C4, is the fourth C key on an 88-key piano as you're counting from the left side of the keyboard.
Place the pinky finger of your right hand on the second E above middle C, which is the first E key above the A key you are playing.
Press down with both fingers at the same time to strike an A5 chord. You can play this arrangement in any octave on the piano, not just the one immediately above middle C. This note combination is known as the root position.
Invert the chord by playing the E key with your thumb, making it the bottom note, and placing your pinky on the A key three steps above. There won't be as much space between these intervals as there was in the first chord you played because it is now inverted. You're playing the fifth of the chord on the bottom instead of on the top.
You can play this chord with the left hand, the right hand, or both. You can use this theory to play other "5" chords as well. For instance, if you wanted to play a D5 chord, place your thumb on the D key and play an A with your pinky either above or below the D key. This is easy to play when you remember that any fifth chord simply consists of the first and fifth tones of a scale played together in any order.