Xiao Ming has participated in three math competitions. The average score of the first two times is 87 points, and the average score of the three times is 89 points. What is the score of Xiao Ming's third math competition?
小明参加了三次数学竞赛，前两次的平均成绩是87分，三次的平均成绩是89分，小明第三次数学竞赛的成绩是多少分？
<gadget id="calculator">89 * 3</gadget>
<output>267</output>

<gadget id="calculator">87 * 2</gadget>
<output>174</output>

<gadget id="calculator">267 - 174</gadget>
<output>93</output>

<result>93</result>