Rhythm is often the most important part of the music. And to play in the right rhythm we must know how to count and feel the time. In this workshop we will explore, in a playful, creative, and collaborative way, a very old relationship: that between music and numbers. We will compose rhythms and beats, with the support of technology: computers, tablets, synthesizers, and other keyboards. Some of the applications we will use are free and open access, so you can continue to use them later, and show them to family and friends.