Perfect! You can have 5 Pizza Shops, or 6 Pizza Shops. You can't have 5.5 Pizza Shops. Thus, this is a discrete variable. Whereas, you can travel at 68.3567... km/h. So, speed is a continuous variable.
QM has a lot to say about the discreteness of many quantities &emdash quantities that we normally think of as being continuous. Let us consider Energy.