Any free keyboard mobile app is your friend if you don't have access to a piano or keyboard.
Here are the excerpts we played with in our session. We'll take these multi-part pieces and make them much more approachable. My method is usually to make the default the melody, and provide one simple optional harmony line for students that feel up to the challenge. Like I mentioned on the other page, I also offer students the opportunity to 'choose your own adventure' and create their own harmony based on their musical instincts. This is something I allow only with students that who advanced and trusted.