2018年第22届广东世界少年奥林匹克数学竞赛四年级竞赛决赛第5题5分
\textbf{(2018 Youth Mathematics Olympics, Primary 4, Question \#5)~}  A certain school district holds the "Xinmiao Cup" primary school football tournament, with a total of $$10$$ football teams participating. The tournament adopts a round-robin system, and each team has to play against all other teams. According to the points ranking, these matches are arranged to be played on the football fields of $$3$$ schools. On average, how many matches should be arranged for each school?（$\textasciitilde\textasciitilde\textasciitilde\textasciitilde\textasciitilde\textasciitilde$）  某学区举行``新苗杯''小学生足球赛，共有$$10$$个足球队比赛，比赛采取循环制，每个队都要和其他各队赛一场，根据积分排名次，这些比赛分别安排在$$3$$个学校的球场上进行，平均每个学校要安排（$\textasciitilde\textasciitilde\textasciitilde\textasciitilde\textasciitilde\textasciitilde$）场比赛． 
拓展思维->能力->运算求解 Overseas Competition->知识点->组合模块->逻辑推理->体育比赛
一共要进行的比赛场次：$$1+2+3+4+\cdots \cdots +9=45$$（场），  则平均每个学校安排的场次：$$45\div 3=15$$（场）． 