Ding Ding, Jia Jia, and Lan Lan do sit-ups. It is known that the average number of sit-ups done by the three people is 91, Ding Ding does 98, Jia Jia does 92, how many does Lan Lan do?
丁丁，佳佳，兰兰三个做仰卧起坐，已知三个人做的个数的平均数是91个，丁丁做了98个，佳佳做了92个，兰兰做多少个？
<gadget id="calculator">91 * 3</gadget>
<output>273</output>

<gadget id="calculator">98 + 92</gadget>
<output>190</output>

<gadget id="calculator">273 - 190</gadget>
<output>83</output>

<result>83</result>