Xiaojun and Xiaobing originally had 70 stamps in total. After Xiaojun gave Xiaobing 15 stamps, they both had the same number of stamps. It turns out how many stamps Xiaojun has.
小军和小兵原来共有70张邮票，小军给了小兵15张邮票后两人的邮票就一样多了．原来小军有多少张邮票．
<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<gadget id="calculator">70 + 30</gadget>
<output>100</output>

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

<result>50</result>