Can a song that is taught using an 88-key piano be played on a 61-key keyboard?
Yes, as long as the range of the song doesn’t go too high or too low. In most cases, that will be true. If the song does exceed the range, you can usually transpose it into a different key to make it fit. Most 61-key keyboards are electronic, and offer a transpose function which shifts the entire range of the keyboard up or down, so you can accommodate almost any piece of music.
