There are 10 players participating in a chess match, they are from teams A, B, and C. Each player plays a set with the other 9 players. The winner of each set gets 1 point, the loser gets 0 points, and the tie gets 0.5 points each. As a result, the average score of team B is 3.6 points, and the average score of team C is 9 points, so how many points is the average score of team A?
一次象棋比赛共有10位选手参加，他们分别来自甲、乙、丙3个队．每人都与其余9人比赛一盘，每盘胜者得1分，负者得0分，平局各得0.5分．结果乙队平均得分为3.6分，丙队平均得分为9分，那么甲队平均得多少分？
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">10 * (9/2)</gadget>
<output>45</output>

<gadget id="calculator">45 - 9</gadget>
<output>36</output>

<gadget id="calculator">3.6 * 5</gadget>
<output>18</output>

<gadget id="calculator">36 - 18</gadget>
<output>18</output>

<gadget id="calculator">9 - 5</gadget>
<output>4</output>

<gadget id="calculator">18 / 4</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>