Xiaojun participated in three math competitions, with an average score of 84 points. It is known that the average score of the previous two is 82 points. How many points did he score the third time?
小军参加三次数学竟赛，平均成绩是84分．已知前两次平均成绩是82分．他第三次得了多少分？
<gadget id="calculator">84 * 3</gadget>
<output>252</output>

<gadget id="calculator">82 * 2</gadget>
<output>164</output>

<gadget id="calculator">252 - 164</gadget>
<output>88</output>

<result>88</result>