In a rope skipping competition, the average score of Xiaohua's two jumps is 120, so that the average score of three jumps is 123, how many times should Xiaohua jump for the third time.
在一次跳绳比赛中，小华两次跳的平均成绩是120个，要使三次跳的平均成绩是123个，小华第三次应跳多少个．
<gadget id="calculator">123 * 3</gadget>
<output>369</output>

<gadget id="calculator">120 * 2</gadget>
<output>240</output>

<gadget id="calculator">369 - 240</gadget>
<output>129</output>

<result>129</result>