In the final test, Xiaoli's average score in the three subjects of Chinese, Mathematics, and Foreign Languages was 90 points, of which the foreign language score was 92 points. Find the average score of the two subjects of Chinese and Mathematics.
期末测试，小丽语文、数学、外语这三门课的平均成绩是90分，其中外语是92分．求语文、数学这两门课的平均分．
<gadget id="calculator">90 * 3</gadget>
<output>270</output>

<gadget id="calculator">270 - 92</gadget>
<output>178</output>

<gadget id="calculator">178 / 2</gadget>
<output>89</output>

<result>89</result>