Jerk off kids in my boxing gym

We were doing our routine hundred jumping jacks in class today and everyone has to count along with the lead, and if they mess around we have to start over. A kid that surprisingly had been there a while and seemed to be respectful was being a comedian trying to show off for some girls in the class and messed up the count at least 5 times, resulting in every kid in the class who takes the training seriously (a select few including myself) doing about 400 jumping jacks before we actually got on the bags or worked on footwork.