Five students participated in the mathematics competition, and the average score of 4 of them was 79 points. After adding Zhang Hua's score, the average score was 81 points. How many points did Zhang Hua score in the math competition?
5个同学参加数学竞赛，其中4人的平均成绩是79分，加上张华的分数后，平均成绩是81分．张华数学竞赛得了多少分．
<gadget id="calculator">81 * 5</gadget>
<output>405</output>

<gadget id="calculator">79 * 4</gadget>
<output>316</output>

<gadget id="calculator">405 - 316</gadget>
<output>89</output>

<result>89</result>