Xiaoyun took 4 homework exams. Before the math results were announced, her average score on the three subjects was 89. After the math results were announced, her average score reached 90. What is Xiaoyun's math score?
小云参加4门功课考试，数学成绩公布前，她三门功课的平均成绩是89分，数学成绩公布后，她的平均成绩达到90分，小云的数学成绩是多少分．
<gadget id="calculator">90 * 4</gadget>
<output>360</output>

<gadget id="calculator">89 * 3</gadget>
<output>267</output>

<gadget id="calculator">360 - 267</gadget>
<output>93</output>

<result>93</result>