The number of reeds in an accordion multiplies in a similar way, plus you need a reed for pushing and pulling if you want the same sound in both directions. A f

The number of reeds in an accordion multiplies in a similar way, plus you need a reed for pushing and pulling if you want the same sound in both directions. A full-sized accordion typically has four sets of treble reeds, though three is also common and there are a few with five.