Xiaogang collected 80 stamps, which is 20 less than Xiaojun's twice. How many stamps did Xiaojun collect?
小刚收集了80张邮票，比小军的2倍少20张，小军收集了多少张邮票？
<gadget id="calculator">80 + 20</gadget>
<output>100</output>

<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<result>50</result>