This app can easily check the sound and the display on the keyboard of the chord tone of musical chords.
If you would like to use features such as playing on a large keyboard or creating chord progressions, try iOS app "Piano Chords Master".
The chord buttons are arranged so that you can easily check the sound of the chord progression, and it supports chord changes.
In either case, when the chord button is tapped, the selected chord is played and the chord tone is displayed on the keyboard.
You can select from the following patterns for the chord button list display.